It's my impression that the SHO Shop y pipe is substantially similar to the BAT y pipe now available. I did get mine with the high flow cat. Did not take it to a dyno to see for sure, but I'd guess it was a 5+ HP kick in the pants, maybe even more. Did not knock my socks off, but it was enough on an improvement to addict me into getting other mods subsequently.

MSDS, SHO-shop Y, custom 2.5" catback; xcal2; 63mm TB, K&N 3530; Koni struts, Aussie bar; THaines forks, Quaife, SpecII, UR fly; DMD; Nima UD pullies; Stazi brakes; f&r Pole120 mounts. Just a daily commuter car. Silver '98 SVT E0 #3159