I was very "scared" to get a catless DP mainly due to it's smell. You might wana read my thread
http://www.e90post.com/forums/showthread.php?t=731298
All in all, I do not regret getting it. The smell is literally less than a lawnmower. The power gains are defiantly noticeable. The smell only hits me if I come to a quick stop after some spirited driving