Looks like that slide wasn't all mud. That's a lot of pressure hitting your suspension from the side. I'd be under there checking ALL the rear suspension components. Look for anything bent, recheck torque specs especially on new parts.
I'd also check the trunk to see if anything came loose like spare tire, jack, ext. lol. Sometimes it's the simplest thing.
08 GT 5spd
Spectra CAI, Comp Cam Detroit Rockers, Kooks headers w/catted H-pipe, Revolution Automotive dyno tuned, FB430 race mufflers, 3.55s, JLT catch can, BMR Lca's and relo brackets. Prothane motor mounts and sway bar bushings.
20% tint, smoked markers and tail lights w/sequentials. Clear front signal covers, series 3 chin spoiler.