The 335i will need FBO to be ahead of the M, a simple tune won't be enough. I've come across 2 stage 1 335i in my ownership and both were multiple car lengths behind by 200.
If all you care about is straightline speed the M3 is not the ideal choice, your 500hp/4000lbs C63 is. It arguably isnt any better of a DD as there is no way to put power to the ground on the stock 255s before 3rd gear and drinks a lot more fuek and goes through consumables pretty much twice as fast (tires, brakes).
To claim the only good thing about the M3 is the DCT lessens any credibility you might have in this thread. The S65 is a multiple Ward's engine of the year recipient and the M3 was the benchmark of the uber V8 sedan generation. The only way I can get 17L/100 is revving out each gear on my commute and looking like a madmen, FYI top of 3rd is 185.