overpipe size
 

The bigger thbe better the flow?....i see the stock is 2.1 and i see aftermarket 2.25-3"....jw before my friend purchase one...tx

My advice would be to buy a quality 2.5inch unless you're going to get a turbo kit.

my friend isnt going turbo he just wanna squeeze some restrictive power from the dp and op so he was wondering if it makes any difference in size of op for better flow...that is something i dont know hehe....thanks you

Is he going to replace the headers? If not I would not even worry about it.

yes i believe he's ordering a header next week...i believe hes replacing header, op and dp...i told him since he has a muffler delete that his car is going to be so damn loud its going to annoy his neighbors but its his car so idk...i have all the tools so im helping him install...

Yeah he'll probably put the stock catback on....

For NA i'd go 2.5inch and catted.