Swapping to an x-pipe system and after-cat exhaust brings about a 10 rwhp increase.
 

This is said in the May issue of Muscle Mustang and Fast Fords on page 116 about the S-197s. Wow if that is the case why didn't Ford do this in the first place. Anyone ever heard of this? My local Mustang shop said that before Ieven read this in the May issue. This is really news to me. Anyone?

RE: Swapping to an x-pipe system and after-cat exhaust brings about a 10 rwhp increase.
 

Some will say 10, some will say 8, some will say 5. Whatever the number, it does make a difference.

RE: Swapping to an x-pipe system and after-cat exhaust brings about a 10 rwhp increase.
 

o/r x 7-10.......catback = neglibable

RE: Swapping to an x-pipe system and after-cat exhaust brings about a 10 rwhp increase.
 

please explain further. I know without cats you are getting more performance however it said with cat-backs and x-pipe. Meaning no axlebacks but catbacks and x-pipe.

RE: Swapping to an x-pipe system and after-cat exhaust brings about a 10 rwhp increase.
 

I've seen claims of 20hp gain from the splice-in FRPP X. Pretty ridiculous sounding.

RE: Swapping to an x-pipe system and after-cat exhaust brings about a 10 rwhp increase.
 

Yeah UPR and Pypes claims 20 with the x-pipe but no cats. It's more like 8 to the wheels.