Would a smaller or larger exhaust make your car go faster?

Exhaust needs to size for your engine/hp,factory exhaust is smaller than idea and is designed for being quieter and for cost. Too bid you lose performance/ground clearance. Exhaust needs some back pressure for low end torque, plus large dual exhaust adds weight to the vehicle hurting performance.

A good rule of thumb...

single exhaust

2.5inch pipe is good for 200hp

3inch -300

dual

2.5inch- 400hp

3inch - 500/550hp