for a n/m motor go with a 2.5 the 3 inch will kill you bottom end.

 

What's an n/m motor? You mean n/a?

 

I was assumeing he ment non moded?? But either way 3inch cat back is good but id get a 2.5 DP

 

ya i had a bit of a typo there I ment n/a, naturaly asprated. The only reason to get a 3 inch exaust is to move air quicker. If you have a 1 inch exaust its going to create more back pressure then a 3 inch exaust. Because all of the air leaving the motor has to force its way though the tiny exaust, where in the bigger exaust there is more room to move the air making it easier for the air to exit the car. thus making it easier for a turbo to spool up becuase their is no back pressure, the air can leave the motor quicker. This is what you wnat for a turboed car but for a car with out a turbo less back pressure isant nesscialry a good thing. A plus is that you will get more top end but you lose torque. A 3 inch exaust can be put on a n/a 4cyl, its not going to hurt it but you best bet is to have a bit of back pressure for some torque. Rember folks you can have all the horse power in the world but its the torque that gives you the get up and go. Also you can get a 3 inch exaust for looks, just run a cayt and a resinator and that will beef up the back pressure.

 

Good point I hadn't thought about Non Modded as an option there LOL.... hmmm....

 

To clearify what I was saying about the exhaust. I wouldnt get bigger than 2.5 for a N\A car. if it is a turbod car 1G or 2G thats what I was saying to get a 2.5 DP and a 3 cat back.

 

Yeah I was gonna say you'd want a 3" for a turbo engine.