yeah you tune the rears out, ive heard u dont have to, they will just cause a cel.

 

I bought some mandrel bent tubing from Jegs (in a kit) and had them weld in a true duel. dont even mess around with all the clamps and ****. Do it once and do it right .trust me, I bought my exhaust twice by starting out with a cat back. It really only costs a little more to get a true dual set-up.