diff --git a/app/pages/component-category/[id]/edit.vue b/app/pages/component-category/[id]/edit.vue
index 184d233..8665930 100644
--- a/app/pages/component-category/[id]/edit.vue
+++ b/app/pages/component-category/[id]/edit.vue
@@ -41,6 +41,14 @@
         show-resolved
       />
     </div>
+
+    <SyncConfirmationModal
+      :preview="syncPreviewData"
+      :open="showSyncModal"
+      :loading="syncLoading"
+      @confirm="handleSyncConfirm"
+      @cancel="handleSyncCancel"
+    />
   </main>
 </template>
 
@@ -48,7 +56,7 @@
 import { computed, onMounted, ref } from 'vue'
 import { useHead, useRoute, useRouter } from '#imports'
 import ModelTypeForm from '~/components/model-types/ModelTypeForm.vue'
-import { getModelType, updateModelType, type ModelTypePayload } from '~/services/modelTypes'
+import { getModelType, updateModelType, syncPreview, syncExecute, type ModelTypePayload, type SyncPreviewResult } from '~/services/modelTypes'
 import type { ComponentModelStructure } from '~/shared/types/inventory'
 import { useComponentTypes } from '~/composables/useComponentTypes'
 import { useToast } from '~/composables/useToast'
@@ -62,6 +70,10 @@ const { loadComponentTypes } = useComponentTypes()
 const loading = ref(true)
 const saving = ref(false)
 const initialData = ref<Partial<ModelTypePayload> | null>(null)
+const showSyncModal = ref(false)
+const syncLoading = ref(false)
+const syncPreviewData = ref<SyncPreviewResult | null>(null)
+const pendingPayload = ref<Partial<ModelTypePayload> | null>(null)
 
 const title = computed(() =>
   initialData.value?.name
@@ -125,10 +137,29 @@ const handleSubmit = async (payload: Parameters<typeof updateModelType>[1]) => {
       ...payload,
       description: payload?.notes ?? null,
     }
-    await updateModelType(id, enrichedPayload)
-    await loadComponentTypes({ force: true })
-    showSuccess('Catégorie de composant mise à jour avec succès.')
-    await navigateBackToList()
+
+    // Get sync preview BEFORE saving
+    const preview = await syncPreview(id, enrichedPayload.structure || {})
+
+    const hasImpact = preview && (
+      Object.values(preview.additions || {}).some(v => v > 0)
+      || Object.values(preview.deletions || {}).some(v => v > 0)
+      || Object.values(preview.modifications || {}).some(v => v > 0)
+    )
+
+    if (hasImpact) {
+      // Show modal for confirmation
+      pendingPayload.value = enrichedPayload
+      syncPreviewData.value = preview
+      showSyncModal.value = true
+    } else {
+      // No impact — save directly + sync
+      await updateModelType(id, enrichedPayload)
+      await syncExecute(id, { confirmDeletions: false, confirmTypeChanges: false })
+      await loadComponentTypes({ force: true })
+      showSuccess('Catégorie de composant mise à jour avec succès.')
+      await navigateBackToList()
+    }
   } catch (error) {
     showError(normalizeError(error))
   } finally {
@@ -136,6 +167,39 @@ const handleSubmit = async (payload: Parameters<typeof updateModelType>[1]) => {
   }
 }
 
+const handleSyncConfirm = async () => {
+  if (!pendingPayload.value) return
+  const id = String(route.params.id)
+
+  syncLoading.value = true
+  try {
+    const hasDeletions = syncPreviewData.value && Object.values(syncPreviewData.value.deletions || {}).some(v => v > 0)
+    const hasModifications = syncPreviewData.value && Object.values(syncPreviewData.value.modifications || {}).some(v => v > 0)
+
+    await updateModelType(id, pendingPayload.value)
+    await syncExecute(id, {
+      confirmDeletions: !!hasDeletions,
+      confirmTypeChanges: !!hasModifications,
+    })
+    await loadComponentTypes({ force: true })
+    showSuccess('Catégorie de composant mise à jour avec succès.')
+    await navigateBackToList()
+  } catch (error) {
+    showError(normalizeError(error))
+  } finally {
+    syncLoading.value = false
+    showSyncModal.value = false
+    pendingPayload.value = null
+    syncPreviewData.value = null
+  }
+}
+
+const handleSyncCancel = () => {
+  showSyncModal.value = false
+  pendingPayload.value = null
+  syncPreviewData.value = null
+}
+
 onMounted(() => {
   loadCategory()
 })
diff --git a/app/pages/piece-category/[id]/edit.vue b/app/pages/piece-category/[id]/edit.vue
index e42ebed..9781dde 100644
--- a/app/pages/piece-category/[id]/edit.vue
+++ b/app/pages/piece-category/[id]/edit.vue
@@ -41,6 +41,14 @@
         show-resolved
       />
     </div>
+
+    <SyncConfirmationModal
+      :preview="syncPreviewData"
+      :open="showSyncModal"
+      :loading="syncLoading"
+      @confirm="handleSyncConfirm"
+      @cancel="handleSyncCancel"
+    />
   </main>
 </template>
 
@@ -48,7 +56,7 @@
 import { computed, onMounted, ref } from 'vue'
 import { useHead, useRoute, useRouter } from '#imports'
 import ModelTypeForm from '~/components/model-types/ModelTypeForm.vue'
-import { getModelType, updateModelType, type ModelTypePayload } from '~/services/modelTypes'
+import { getModelType, updateModelType, syncPreview, syncExecute, type ModelTypePayload, type SyncPreviewResult } from '~/services/modelTypes'
 import type { PieceModelStructure } from '~/shared/types/inventory'
 import { usePieceTypes } from '~/composables/usePieceTypes'
 import { useToast } from '~/composables/useToast'
@@ -62,6 +70,10 @@ const { loadPieceTypes } = usePieceTypes()
 const loading = ref(true)
 const saving = ref(false)
 const initialData = ref<Partial<ModelTypePayload> | null>(null)
+const showSyncModal = ref(false)
+const syncLoading = ref(false)
+const syncPreviewData = ref<SyncPreviewResult | null>(null)
+const pendingPayload = ref<Partial<ModelTypePayload> | null>(null)
 
 const title = computed(() =>
   initialData.value?.name ? `Modifier « ${initialData.value.name} »` : 'Modifier une catégorie de pièce',
@@ -123,10 +135,29 @@ const handleSubmit = async (payload: Parameters<typeof updateModelType>[1]) => {
       ...payload,
       description: payload?.notes ?? null,
     }
-    await updateModelType(id, enrichedPayload)
-    await loadPieceTypes({ force: true })
-    showSuccess('Catégorie de pièce mise à jour avec succès.')
-    await navigateBackToList()
+
+    // Get sync preview BEFORE saving
+    const preview = await syncPreview(id, enrichedPayload.structure || {})
+
+    const hasImpact = preview && (
+      Object.values(preview.additions || {}).some(v => v > 0)
+      || Object.values(preview.deletions || {}).some(v => v > 0)
+      || Object.values(preview.modifications || {}).some(v => v > 0)
+    )
+
+    if (hasImpact) {
+      // Show modal for confirmation
+      pendingPayload.value = enrichedPayload
+      syncPreviewData.value = preview
+      showSyncModal.value = true
+    } else {
+      // No impact — save directly + sync
+      await updateModelType(id, enrichedPayload)
+      await syncExecute(id, { confirmDeletions: false, confirmTypeChanges: false })
+      await loadPieceTypes({ force: true })
+      showSuccess('Catégorie de pièce mise à jour avec succès.')
+      await navigateBackToList()
+    }
   } catch (error) {
     showError(normalizeError(error))
   } finally {
@@ -134,6 +165,39 @@ const handleSubmit = async (payload: Parameters<typeof updateModelType>[1]) => {
   }
 }
 
+const handleSyncConfirm = async () => {
+  if (!pendingPayload.value) return
+  const id = String(route.params.id)
+
+  syncLoading.value = true
+  try {
+    const hasDeletions = syncPreviewData.value && Object.values(syncPreviewData.value.deletions || {}).some(v => v > 0)
+    const hasModifications = syncPreviewData.value && Object.values(syncPreviewData.value.modifications || {}).some(v => v > 0)
+
+    await updateModelType(id, pendingPayload.value)
+    await syncExecute(id, {
+      confirmDeletions: !!hasDeletions,
+      confirmTypeChanges: !!hasModifications,
+    })
+    await loadPieceTypes({ force: true })
+    showSuccess('Catégorie de pièce mise à jour avec succès.')
+    await navigateBackToList()
+  } catch (error) {
+    showError(normalizeError(error))
+  } finally {
+    syncLoading.value = false
+    showSyncModal.value = false
+    pendingPayload.value = null
+    syncPreviewData.value = null
+  }
+}
+
+const handleSyncCancel = () => {
+  showSyncModal.value = false
+  pendingPayload.value = null
+  syncPreviewData.value = null
+}
+
 onMounted(() => {
   loadCategory()
 })
diff --git a/app/pages/product-category/[id]/edit.vue b/app/pages/product-category/[id]/edit.vue
index 9875810..f687fb5 100644
--- a/app/pages/product-category/[id]/edit.vue
+++ b/app/pages/product-category/[id]/edit.vue
@@ -41,6 +41,14 @@
         show-resolved
       />
     </div>
+
+    <SyncConfirmationModal
+      :preview="syncPreviewData"
+      :open="showSyncModal"
+      :loading="syncLoading"
+      @confirm="handleSyncConfirm"
+      @cancel="handleSyncCancel"
+    />
   </main>
 </template>
 
@@ -48,7 +56,7 @@
 import { computed, onMounted, ref } from 'vue'
 import { useHead, useRoute, useRouter } from '#imports'
 import ModelTypeForm from '~/components/model-types/ModelTypeForm.vue'
-import { getModelType, updateModelType, type ModelTypePayload } from '~/services/modelTypes'
+import { getModelType, updateModelType, syncPreview, syncExecute, type ModelTypePayload, type SyncPreviewResult } from '~/services/modelTypes'
 import type { ProductModelStructure } from '~/shared/types/inventory'
 import { useProductTypes } from '~/composables/useProductTypes'
 import { useToast } from '~/composables/useToast'
@@ -62,6 +70,10 @@ const { loadProductTypes } = useProductTypes()
 const loading = ref(true)
 const saving = ref(false)
 const initialData = ref<Partial<ModelTypePayload> | null>(null)
+const showSyncModal = ref(false)
+const syncLoading = ref(false)
+const syncPreviewData = ref<SyncPreviewResult | null>(null)
+const pendingPayload = ref<Partial<ModelTypePayload> | null>(null)
 
 const title = computed(() =>
   initialData.value?.name ? `Modifier « ${initialData.value.name} »` : 'Modifier une catégorie de produit',
@@ -123,10 +135,29 @@ const handleSubmit = async (payload: Parameters<typeof updateModelType>[1]) => {
       ...payload,
       description: payload?.notes ?? null,
     }
-    await updateModelType(id, enrichedPayload)
-    await loadProductTypes({ force: true })
-    showSuccess('Catégorie de produit mise à jour avec succès.')
-    await navigateBackToList()
+
+    // Get sync preview BEFORE saving
+    const preview = await syncPreview(id, enrichedPayload.structure || {})
+
+    const hasImpact = preview && (
+      Object.values(preview.additions || {}).some(v => v > 0)
+      || Object.values(preview.deletions || {}).some(v => v > 0)
+      || Object.values(preview.modifications || {}).some(v => v > 0)
+    )
+
+    if (hasImpact) {
+      // Show modal for confirmation
+      pendingPayload.value = enrichedPayload
+      syncPreviewData.value = preview
+      showSyncModal.value = true
+    } else {
+      // No impact — save directly + sync
+      await updateModelType(id, enrichedPayload)
+      await syncExecute(id, { confirmDeletions: false, confirmTypeChanges: false })
+      await loadProductTypes({ force: true })
+      showSuccess('Catégorie de produit mise à jour avec succès.')
+      await navigateBackToList()
+    }
   } catch (error) {
     showError(normalizeError(error))
   } finally {
@@ -134,6 +165,39 @@ const handleSubmit = async (payload: Parameters<typeof updateModelType>[1]) => {
   }
 }
 
+const handleSyncConfirm = async () => {
+  if (!pendingPayload.value) return
+  const id = String(route.params.id)
+
+  syncLoading.value = true
+  try {
+    const hasDeletions = syncPreviewData.value && Object.values(syncPreviewData.value.deletions || {}).some(v => v > 0)
+    const hasModifications = syncPreviewData.value && Object.values(syncPreviewData.value.modifications || {}).some(v => v > 0)
+
+    await updateModelType(id, pendingPayload.value)
+    await syncExecute(id, {
+      confirmDeletions: !!hasDeletions,
+      confirmTypeChanges: !!hasModifications,
+    })
+    await loadProductTypes({ force: true })
+    showSuccess('Catégorie de produit mise à jour avec succès.')
+    await navigateBackToList()
+  } catch (error) {
+    showError(normalizeError(error))
+  } finally {
+    syncLoading.value = false
+    showSyncModal.value = false
+    pendingPayload.value = null
+    syncPreviewData.value = null
+  }
+}
+
+const handleSyncCancel = () => {
+  showSyncModal.value = false
+  pendingPayload.value = null
+  syncPreviewData.value = null
+}
+
 onMounted(() => {
   loadCategory()
 })