I'm fortunate that I live somewhere that doesn't require emissions, but I know that's been painful for some folks since BMS had to drop theirs. Looks like Wedge Performance has solved that:
http://www.x-ph.com/x-kitty-n54-downpipe-fix-dp-fix/
$140
-Rich
http://www.x-ph.com/x-kitty-n54-downpipe-fix-dp-fix/
$140
-Rich