I have a 87 N/A that needs an exhaust so I was goin to go 3in from manifold back Nocat into a 2.5 in dyno max bullet muff. I want it to be street able and not to loud. should I run 2.5 in pipe instead or change the muff idea. thanks dave

 

Im not sure about the mufflers, but I think that 3"-2.5" might be a little too big. You wanna keep some backpressure, or your low-end power would be terrible. maybe try 2.5 -2.25, or just straight 2.5 of you want it that big. I just think that 3" might be a little overkill. Just my $.02

 

If you don't care about the power, do it. But you might want to look at the exhaust write up on Mazdatrix beforehand. Too big a pipe will reduce your HP.