I just installed PE on a e92 335i, and was surprised by the differences compared to PE on my e90 330i. It's not quite as deep or "rumbly", at least not yet after 1000 km. The turbos seem to smooth out the exhaust, I suppose. Still fantastic, well worth it!
Anyway, I'm also getting drone cruising around 2500 rpm in the e92, which is common on the highway. The e90 has zero drone IMO. I'll have to check for leaks at the clamps...but it's surprising that could cause drone. I'm wondering if mounting it slightly differently (tighter, or shifted somehow) could effect the resonance of the system.
Best idea is to compare to someone else at a meet with the same setup
Good excuse to go to a meet
