I am looking for the best header and x-pipe combo package for the buck. Any one have any experience with these? I've got the borla cat back and want to add some umph to it.

 

Probably JBA LTs with JBA H-Pipe. You can pretty much bet that both of those products were engineered to work more efficient when combined.

With choosing any LTs and h-pipe/x-pipe...it won't be as easy to find a more efficient setup than getting both from the same MFG.