Dude, that sounds REALLY good. I don't have the Challenge Sport pipe but believe I have most of that sound. What a great decision I made and I'm now sad you are selling your car. Good luck with everything bump.
"what I'm driving here...is an ending." Jeremy Clarkson
2011 Alpine White BMW M3 6mt ZCP Coupe
2008 Alpine White BMW 328i 6mt Coupe (retired 06/21/11)