13" Wheels With KH Disc Brakes

why would you even want to....
those 13" tires are the limiting factors with 9" drums already. You can't hardly stop on 13s with drums, nevermind dual 4-piston calipers.

Forget 1" adapters on the front with factory wheels; it will destroy your scrub radius and you will end up chasing the car all over the road.

Speak for yourself. My 9" drums and 13" tires stop great. They do their job just fine.