Originally Posted by rxforspeed

It's all about torque for a good streetable car. If you're more concerned with higher RPM HP and could care less about low end torque, then by all means run the biggest (or just big) pipe you can fit. I know that rotary engine's aren't known for their impressive low end torque, but I think I'm still going to stick with 2.25" and 2.5" max when I get around to adding my turbo. I want a car that'll perform in traffic when I need it to, at RPM levels that don't draw unnecessary attention...

Just plan out your mods and consider what the goal and main purpose of the car is. If it's going to be street-driven and is mostly stock under the hood you may want to keep the 2.25" or even go down to 2". The exhaust alone won't make the car-it's all the mods working together with each other...