Help

i wanted to know how can you know how big your exhaust should be for best performance, because im only 17 and i keep hearing people say that they have a 2 1/4" exhaust and some say 2 1/2" and all kinds but how can you know witch one you need? does it matter how much horsepower you have?? -thanks

im so lucky the barracuda you see there is my dad's but will be my christmas present really soon!!!

This is going to sound funny but I actually saw a guy running dual 3 inch exhaust on a 340. I was like aren't those maybe a little too big for that engine and he was like nope... He wanted to put 3 1/4 inch duals on it. But if you want to put 2 1/2 on it.. it'll probably sound really nice.