ok so my gf gna get me an exhaust system for my bday. anyways im unsure what im after. i called up acouple of exhaust places and they quoted around the 4-500 mark. i told them i wanted a 2.5" catback system but they said that i should stay with the 2.25 setup. reading on here seems like 2.5 is the way to go. anyways do i want a 2.5" straight pipe from the catylic converter? to the muffler? thanks