What do they do and will you gain horsepower?

 

Well you already have one on your car. The H-pipe is the midpipe of mustangs. From back to front you have tips, mufflers, mid-pipe, headers. You can get aftermarket H-pipes, either Off Road H-pipe meaning there is no cats or High flow H-pipes with 2 hi-flow cats. Yes they will add horsepower and they will make your car sound different. Typical gains are around 5-10 rwhp.

 

which are better

 

I got an O/R MAC. It's cheap but good.

 

O/R pipes are better, cats restrict airflow so offroad pipes have 0 cats while hi-flow pipes have 2. There isnt a huge differnece between the two but the O/R will sound better and perform better.

 

where can i get some

 

IDK look around, I got mine from a local store AMP performance here in Arizona but on pretty much any mustang part site you can find either pipe.

 

I got mine off of ebay fron brenspeed for like $135 shipped i think.

 

if you want power go for an X pipe, if you want sound go for an H pipe..now o/r X is very loud which is what i have teamed up with my SLP loud mouth exhaust..but H the sound is a little beefier..but at the cost of a few ponies....

-Mike

 

The X and H have a very little difference in performance gains so you might as well just buy for the sound.