Ok so i know it's been done once before by a member here but i can't find the threads. My resale value on my 2.8Q is pants, so i'm looking at dropping an s4 engine into it or Rs4 engine. The latter is assume would be rare to find and then cost more than it's worth to do. I've found an s4 engine on ebay for £1500 So can i simply plumb an s4 engine into my a4 2.8 quattro? What others changes would be needed? Thanks for your help.