The GT500KR has the 500hp GT500 motor with an FRPP CAI and matching computer tune boosting it to 540hp. Same thing for the 2010 GT500, except the CAI tube bends the conical filter down towards the grill opening (which is why they relocated the coiled cobra embled in the grill to the passenger side for 2010). Any '07 to '09 GT500 owner can purchase the exact same FRPP CAI and tune used in the GT500KR to upgrade their car to 540hp (which I already have).
As far as other differences, the 2010 GT500 gets 19" rims and the upscale interior appointments versus the 18" rims and original S197 interior on the GT500KR. The 2010 GT500 has 3.55:1 gears versus 3.73:1 gears in the GT500KR (The 2010 GT500 gets a taller overdrive 6th gear than the '07 to '09 GT500s so highway mileage doesn't drop). The GT500KR gets a few parts such as the front splitter in carbon fiber instead of the plastic used for all the GT500s.
There are only two main reasons the GT500KR may be worth the $80K MSRP versus the lower cost of a GT500. Exclusivity due to the smaller quantity manufactured (only 1570 KRs for the USA plus 157 more for Canada were produced in total). And the special carbon fiber hood with recessed twist-lock hood latches used on the KR is a beautiful design that looks far superior to any aftermarket manufacturer's attempt at copying it. Ford won't even sell that hood to Shelby for the Shelby SuperSnake (which uses a fiberglass hood of similar but inferior styling). The special hood and the limited volume collector car status are unique to the GT500KR.
By the way, planned GT500KR production was originally announced to be only 1,000. Then it was noted that it would be 1,000 for the USA plus 100 more for Canada, or 1,100 total. Then they upped the count to 1,570 for the USA plus 157 more for Canada, or 1,727 total. The reason for the odd quantity of 1,570 was explained as matching the total production of the original GT500KRs produced back in 1968 (which was 1,053 fastbacks and 517 convertibles). Even if we accept their explanation, what is with the additional 157 KRs made for Canada? There weren't any additional 1968 GT500KRs built specifically for Canada. Sounds to me like they planned on 1,000 KRs (1,100 including Canada) at first, but then it looked like they could sell even more of the ultra high priced Mustangs, so they got greedy and upped the produciton figures.
__________________ 2008 Shelby GT500 torch red with black stripes + sequentials
2001 Cobra mineral grey with 2003 Mach 1 shaker hood
1996 Cobra color-shifting mystic paint + sequentials | 
