My
BTG single axle-back exhaust system [B)] had a
bad harmonic drone at 3K rpm that, even when adding a resonator, wouldn't go away completely.
I finally replaced it with a Mopar 2.5-inch performance dual exhaust system (by Borla) and couldn't be happier.
http://www.ptcruiserlinks.com/forum/...TOPIC_ID=13109