OP, any drone with the Challenge X-Pipe + Muffler? I am running a Dinan + Challenge Street now and was thinking of pairing the Challenge Muffler with the Challenge Street pipe.
Let me know, thanks.
2008 E90 M3 | Interlagos Blue | Speed Cloth | 6MT - A work in progress...
2011 E92 M3 ZCP - Gone, but not forgotten.