there is far far more to making an exhaust than just bunging some pipe under your car and going by the bigger is better route i used to make performance exhausts for a living and no before you say not for power(doesnt)flow!! though if your car is pretty standard and you follow the routing and silencer sizing/placement of the original exhaust then you wont lose anything, most likely wont make much more power 2-3bhp overall and some more noise