I want to get at least one borla XR-1 in my exhaust system. Right now I have a stock exhaust but want to get something better. I do not have to worry about opening up my ports, I will solve that with something else.
I was debating over getting Just one XR-1 in place of the main cat as a pre-silencer and just running straight pipes after that keeping it dual or getting 2 XR-1'S in place of the mufflers at the back and just take out all of the cats.

Also do the positioning of the muffler/pre-silencers make a difference in sound? If so wheres the best positioning for good sound?