The best exhaust that i know of that is H-pipe. I have it on my 2000 gt. It is seriously loud. My friend has a 5.0L mustang cobras with straight pipe and it's not even close to as loud as the H-pipe on my 4.6L gt. Roush has a kit, which is what i have, but that'll cost a $1000 for the PARTS ONLY. I would highly recommend this kit, even on a stock gt it sounds absolutely amazing.