There's been a lot written about this. Search this forum and you'll find quite a bit.
Originally Posted by MJK Z435IS
What is a good exhaust system to give me more sound/performance. Not a lot out there!!!
2006 525 xi, Orient Blue Metallic, Beige leather, Dark Poplar trim, Premium Package, Cold Weather Package
2012 Z4 35i, ED 2/24/12, Melbourne Red Metallic, Black leather, 6 MT, ///
M Sport, Premium Package, Premium Sound Package, Cold Weather Package, Nav, Comfort Access, Alpine HID Angel Eyes, BMWPedals pedal covers, stubby antenna, Extra Enjoyment Package