ok komodo I have heard your car and you DEFINITLY w.o a doubt need exhaust way before rims. No doubt your car sounded amazing from the front but from the back.... alot of ppl at the meet were questioning why ur stock exhaust was rattling like crazy and raspy as hell. One guy was wondering why is sounds "so bad" but he wasnt standing by the engine. I'd get that system U or Rsc36 from UUC and keep the sleeper look for awhile, then get the rims.
also with x-pipes and a manifold you'll make well over 10 hp gains easy, but not so much at peak hp.
Current standings: 98 M3 Track car
Mods: suspension, i/e/fly only
1/4th mile: 13.7@101 on 235/40 streets
Rd Atlanta: 1:44's on RA1's, 1:46 st.trs
95 M3 3.2obd1