5x4" to 5x4.5" dr. diff kit, Questions.

I purchased the dr diff kit with the 11.75" rotors and caliper kit to change over from 5x4" to 5x4.5" and ran into an issue. The wheels i want to use are fr500 wheels and the hub on the rotor that comes in the kit and hits on the wheels center bore. Same as my Saleen mustang. I was wondering if i could machine the snout slightly smaller on each side or if there is something i can get so that i wont have this problem anymore. Dont want to spend another 1300 bucks but id like to be able to use these wheels. Wheels in question are in the second pic. Id also like to be able to swap wheels later on but cant due to the stupid hub size on the rotors. When i purchased it i was under the impression it would be like other rotors without the giant snout poking through.
The wheelstuds will not reach the holes because the snout touches a ridge inside of the center bore which is for the center caps..
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