E36 M3 (S50) no drone custom exhaust?

[aeronaut]

UPDATE, first day on track with the new exhaust. Summary:
S50, Bimmerworld 2 to 1 y-pipe, to 3" Vibrant 1795 18" bottle resonator, to a 3" to 2x2" merge into my previous Stromung muffler.

Bluntly, I'm surprised by how much it changed the power band. Not that it made a huge difference, but a very noticeable one. For track, it's perfect. It basically fattened up 4k-5.5k rpm. Below 3.5k is noticeably less torque, 4-5.5k noticeably more, 6k-7k feels about the same.

Corner exit behind my friends 135i, I pull EXACTLY even down the straight, whereas before, he'd very slowly nudge away from me, gaining ~2 car lengths.

Now, about the sound. It sounds good outside the car, but not as good inside. I think it's the nature of going to single wall tubing, and no choice of resonator or muffler would really fix that.

Overall, while I'd change a few little install and component decisions, I'd definitely do it again for a mostly track car.

[M3kiwi]

A bit late to the conversation, but for future reference.
Euro S50B32
Dynoed at each stage of build.(shows kW and torque)
Track orientated, now I'm getting old I'm looking at swapping out the back box for DD.
Link to my exhaust build.
http://bimmersport.co.nz/topic/43521...2-1997-hackar/