Hello everyone! I am clearly new to the forum of course and new to forum use altogether. I just recently purchased a 07 B7 Quattro with 145,000 Miles about a month ago. It was/is very well maintained, clean inside and out with a majority of it's service intervals done. Since being the third owner and being a first time Audi owner, I love her! I've already gone the extra mile in maintenance and possibly gone to far, lol. I'm in the gradual process of modifying her and have done a serious amount of research and searching. So, now to the topic. Between the A4 and S4 B7's, how much is compatible?

 

A lot is, a lot isn't. Depends on what you're trying to do.

A lot of people upgrade the brakes to S4 brakes. I have an S4 (from a B8, no less) steering wheel in my A4. Just depends on what you are trying to do.