There are so many different choices for exhaust's, what will give me the most horsepower and what is the difference between x and h pipe because everyone seems to be talking about them?

 

This should be in the Pipes, Boost and Juice forum FYI.

Minimal difference btwn X & H. X is said to give you a few more HP, but it’s hardly noticeable. H is said to give you a deeper grumble at idle. I guess it all depends on what your looking for. If it’s strictly performance, go X (but bear in mind gains will be minimal over an H). Personally, I’d go with an off-road X unless you live in a state with emissions in which case you might consider a high-flow X. Also, don’t count out SLP – they make a nice little high flow catted X that is modular (i.e., you can swap out the cats for race inserts [which are basically pieces of stainless steel tubing] making you catted X a race pipe inside about 20 minutes)……

 

do they make the SLP X pipe for LT headers? they sound interesting to me, i wouldnt mind having them for LT's.

 

Yes, and it's a bit cheaper than the X for shorties - here's a link: http://www.lmperformance.com/3675/50.html

 

the SLP can be used with shorties or LT. http://mustangtuning.com/slpxc99.html