muffler question?
what's a good muffler to buy with a 1.75" inlet/3" outlet?
i wanted to go with a magnaflow because of their nice deep low tone but when i searched up magnaflow.com, all of their inlet/outlet sizes for each muffler are the same. i wanted to keep the 1.75" inlet because i only want the sound and want to keep the gas mileage high. also i don't find much point in trying to gain minimal hp on my already slow civic. or should i really expand my piping? if so, how much would my gas mileage go down approximately if i expand it? thanks!