IMHO, Borla is the best sounding exhaust b/c of there not being a raspy tone. I did notice a decent difference in low end, but when I bought the exhaust I was told that you won't notice a big increase until you change the exhaust in front of the cat(headers or y-pipe or both). Have heard the other exhaust (bassani and brullen) and just have to say I love the Borla. Tips are as stated 3.5" and pipe diameter for exhaust is 2.25" non resonated mufflers w/ straight through design
