I did have a set of these, bought them on the intial group buy way back when. These performed flawlessly for me, and the truck made power, no definitive numbers since they went on the same time the Nismo headers did, and without a tune for the headers, between them and the b-pipes I gained 20HP on the dyno. Their construction was flawless, and I loved them. The only reason I do not still have them is because I am going with new headers with a 2.5" collector for the addition of cams very soon. I bought PRT 2.5" to replace them, but for guys that want to stay stock manifolds or find headers with 2.25" collectors such as the Nismo's these are a great addition. You could gut the primary cats then if you wanted and still pass the sniffer test. They worked flawless and code free the entire time on my truck. Great pipes, just wish they were 2.5" now, but that 2.25" will help keep the torque down low on the Titan. There are only two sets of b-pipes made that are the 304 stainless, the Berk's and PRT's, everything else is lower grade stainless and will surface rust, these will not. Once again, great pipes, I would have no reservations to having another set in the future.
For you guys with four cats anyhow, these are high flow metallic cats on the Berk's and will be greater flow than the stockers by far, you will gain with these. For states with a visual, these would probably pass that as well.
