Replicating Existing Product Details to New Product
Would the "Save & Copy Button" plugin suit your needs? It will create a duplicate record, then you can modify the fields that have different specs.
Ah, I think I see the direction you're going with this now...
You could create separate multi-record section editors for each spec type (e.g. engine size, website link, logo etc.). These tables/records would act as your data sources.
On your "products/cars" section editor, you can create fields as Field Type "list" using the spec tables as data sources.
I'd probably set List Options as "Get options from database (advanced)", select the source table, and use "num" for option values with "title/name" for option labels.
When creating "product/car" records you would simply select values from these list fields.
This way when you modify an existing spec record "title/name" field the Label will be updated for any "product/car" record that has it selected.
Does this sound like the direction you're looking to take? Hope this helps.