not 100% I know what your looking for but, where i'm from i have a 00GT with full exhaust (BBK long tube headers, BBK shorty X-pipe w/ no cats, and American Thunder series cat back) which sounds very mean, i haven't noticed a raspy sound to it like a lot of people caim to get.
The other car i have heard with full exhaust is a 5.0 95GT He has BBK headers (not long tube for sure) BBK H-pipe and flow master catback. I hear more of a raspy sounds out of the H-pipe than my X-pipe. It could have somthing to do with his being a 5.0 and mine being a 4.6 but either way you want to go about it they sound real good and very mean.
This is what i've come to understand about H vs. X and that is that the H-pipe will give you more of a muscle sound like out of the 60's and the X-pipe will give you a more exotic sound like an Italian car would have, but with more of a muscle sound. Either way you choose to go you car will sound meaner. I went with the X-pipe because most GTs come with factory H-pipes.
2000 GT
BBK full length headers
BBK shorty X-pipe w/ no cats
Flowmaster American Thunder Series
BBK cool air intake
BBK 75mm Throdle body
BBK Underdrive pullies
BBK chrome valve covers
Ford racing drive line
Hurst short throw shifter
lowered 1.5 inches
03 cobra 18 inch rims
steeda 2 inch hood
steeda front chine splinter
cobra R rear spoiler
black with blue flames airbrushed on