So what exactly are you trying to find out? Yes, it's going to sound different. As to whether or not the borla will sound good with pacesetters, check ls1sounds.com for borla combinations, that's a personal preference. Since everything is stock, you can get whatever you want, you don't necessarily have to go with borla. Pacesetter LTs with ORY and Magnaflow catback exhaust is a good combination too. If you want to stay with your stock exhaust, you can do that also, but you are going to be leaving some horsepower on the table, as the stock exhaust is not as free-flowing as an aftermarket exhaust.