which 5 lug swap for MM konig rims??

I would go with the 94-95 GT/LX spindles. They open up a world of 5 lug wheels. You can go with 94-98 calipers, don't waste your time, go with 99-04 PBR's, dual piston calipers, which retain the stock 10.5" brake rotors from all 94-04 Mustangs. They stop great with the stock FOX booster, master and prop valve. 13" Cobra brakes will require different master, booster and possibly the addition of an aftermarket or adjustable prop valve.

Mark VII rotors allow you to only run a handleful of 5 lug wheels. This is because they don't allow the center caps to fit, the dust cover gets in the way.

if you're going 275 in the rear you'll probably got w/ a 40 series tire, the front w/245 you can go with the 45 series.