JAS 39E - the outside looks the same but the inside is very different.
I have yet to see a production JAS-39E, the F was canceled and the Sea Gripen is a wet dream, so I guess I will take your word for it.
how many original Su-27 parts are in there, and my guess would be "not very many".
Whatever they put in there now has added thousands of pounds, I know that much.