cidsamuth

Okay, I understand the different between the X and H pipe sounds. However, since I already have an O/R Roush exhaust, I'm really concerned about going with an O/R X-pipe because of noise level.

I'm pretty sure that eliminating the cats would have gotten me 10 - 15 HP. Well, what about with aftermarket cats, like the UPR catted X-pipe? Any HP to be gained, or would I be installing it only for the difference in sound between my stock H pipe and the UPR X?

While UPR says it gets "up to" 20 HP out of its catted X-pipe, I really doubt it.

gman73

I have no experience with UPR products but I have heard that they are low quality. A friend of mine who is a co-owenr of a mustang shop says he will not order UPR because of the quality. As far as hp gains, in my experience compared to the stock catted H, O/R midpipes gain hp but lose tq and hi-flow cats gain both hp and tq.

cidsamuth

Thanks, gman. I guess if I want hp gains without the excessive noise, the key will be finding good "high flow" cats.

Do you have a recommendation? I read elsewhere that all the major brands (Kooks, BBK, JBA, etc) use the same cat manufacturer, but don't know if that's true.

UPRDanielle

You will definitely see a power gain from replacing your factory mid pipe with an aftermarket mid pipe. I wouldn't question the quality of UPR's x-pipe's, tho. I had one on my old GT and it sounded great, worked perfect and I had no problems with exhaust leaks. Honestly, I have a Bassani x-pipe in my Cobra only because it's temporary (in the process of installing a turbo) and every oil change I have to adjust and tighten the slip fit pipes and clamps because I ALWAYS have leaks...even put high temp RTV where the pipes meet, and it didn't really help. lol

gman73

Even though I have pypes catted X, I would go with magnaflow tru-X. I got the pypes catted X off a local seller, brand new for $300, so I can't complain. The pypes is PITA to instal as you have to cut the legs to slip in the cats. I ended up taking to an exhaust shop so they could fix it and weld in the cats. Bassani also has slip on cats. I would have these welded on. Also bassani is not a true x pipe but more of a clam shell shaped. It has it's own unique sound.