going to better dp's, like "super-split", or 3" expansion dp's, but the plain split dp's are much better than gutted pre-cats. One example: right now, in Classifieds Z32TT-R is selling a set for $80 (I'm not recommending him or the dp's, I don't know him, but you can check him out on this site.) .... Neither dp's or test pipes will help with sound. What helps is the wrapping.