Which one? Options

[ChOoKmAn]

I have decided the first thing im going to do to my car is get the extractors and sports exhaust with cat but i can decided or know if a 3" or 5" canon would be best... i think a 5 would look better but ive been told by a few ppl that 5's are no good for non turboed cars is this true? as i want performance and looks out of this rig so i may have to make a compromise depending on what you guyz think? oh i have a 5sfe engine if this matters any, and no im not interested in a conversion lol i know the 5sfe isnt the best but i dont want to go that far with what im doing to my car... your thoughts are apprieciated.