O1 GT exhaust? What kind do you have?
 

I am looking to buy a new exhaust for my '01 GT. I want a deep rumbling sound that does'nt drone while cruising. I have been looking at the 3 chamber flowmasters and the Steeda kit. Are 2-1/2" flowtubes better than the stock 2-1/4"? Do bigger tubes increase horsepower on a stock engine? Is it worth the money to replace the stock cats with a Hi-Flo Catlytic Converter X-Pipe? Or should I just change the mufflers?