For the e30 M3 s85 swap a lot of time and money was spent designing a custom intake + manifold to get the car to run properly. Good luck if you think all M5/M6 OEM parts can be used! A lot of custom design and fabrication required...
However, I will say seeing, and hearing, a Dinan-stroked s85 in an e30 M3 is awesome! The already flared fenders were flared some more to get as much tire on the car as possible and that thing still has trouble putting all of its power to the ground
