Exhaust clearance if you have LT's, possibly. Get a new pilot bearing, always when changing a clutch, etc.. As you may or may not know these T56's come with 2 different available gear patterns and also a newer 2012 released version T56 Magnum XL rated for 700 ft. lbs. One with a Lower total gear ratio for First (2:97), Second (2:10), and Third (1:46). The Fourth gear being 1:1 ratio on both selections, then your Overdrive gears Fifth and Sixth also differ from pattern selection. This is a VERY important decision that if not chosen correctly could leave you with a nonreturnable transmission that doesn't perform to your car's capability/needs or your expected outcome. HP/TQ, Weight, Use, Rear gear, Tire size plus other variables should be looked at when making your selection, have a AM tech help advise you on this or even Tremec, but you will get the best service and price through AM. Both come with a Steel SFI rated Bellhousing, Heat/Dust Shield Plate, Cross member, Trans. Mount, Isolated Shifter mount, Shifter and Tremec inscribed ball and utilizes the stock hydraulic clutch system. Oil not included. Buy a new pilot bearing and select a Clutch,Pressure plate and matching Flywheel based on your estimated Torque/HP and use, under the clutch section on the website. I personally have a few "Ponies in the Barn" and one is a 11" GT fully built Coyote from the block up. She has a 76mm Turbo, Return style fuel system (E85), built rear/suspension. And YES I went with a T56 Magnum XL (not just the older T56) with the higher gear ratios because I knew HP/TQ wasn't gonna be an issue in a near stock weight 11' GT. A Quicktime steel SFI bellhousing, McLeod steel flywheel and RXT twin disc clutch was used because of my planned use. On my S197 platform a wiring harness was needed to make a semi-easy install for the electronics to work, like reverse lights, speedometer, etc.. which you may need also. A forum or Mustang fan group page on FB is usually a way to get "Been there done that advice". I went with a custom driveshaft from Justin's Performance Center (JPC). Needless to say I absolutely love having a monster sleeper super car that can handle daily driving or road trips. I hope this can give you/anyone the answers and knowledge they needed to go ahead and make good decisions when upgrading your Mustang or Ford vehicles.