I've got mine dumped before the rear axle. LT's, o/r x pipe and Borla stingers. It gets loud as hell, but like recon said the noise is behind you. If you don't have a problem with NVH, then dumping it shouldn't be a problem. As for scraping goes, usually the mufflers are recessed a bit and if the turn downs are pointed at an angle instead of straight down you shouldn't have issues.
2000 Mustang GT-Former giggle gas addict
1990 Mustang GT w/ Vortech V3
***resident gun idiot***