KH Discs vs 73+ Discs
I voted KH, cuz they re awesome.
However, because of his situation, I would kinda lean towards the single piston set-up.
Naw. I love my KH/Dot5/braided lines set-up. Its been working 100% for 15 years and 125,000 miles with zero maintenance. ZERO. You wont get that with the other.
I can't quite live up to that kind of longevity, but I've put over 50k miles on the pin-style, single piston calipers on my Challenger. In fact, the calipers are the same ones that came with the car, I've never done anything to the calipers themselves, so I have no idea how many miles are on them. They appeared factory when I bought the car, but who knows. When I installed my 11.75" rotors I just changed out the caliper brackets to run the larger disks and installed new pins just because I was in there doing the work. Since then I've changed the pads once, but that's it.
I don't have a set of KH's, so I really can't comment on them too much. The multi-piston set up should actually provide better braking than the single pistons, as long as the seals aren't a problem. I've heard of people having issues with the seals, but AJ seems to have had great luck with them so that may be overblown. But I still think they lose out because of the SBP and difficulty of finding parts, wheels, etc.
If he's considering autoX'ing the car, I would go straight to the 11.75 mopar disks from the B/R bodies as spl440 suggested. It's a bolt on deal if you have 73+ spindles, you just need the rotors, caliper brackets, and at least 15" rims. Doesn't seem like much, but it makes a significant improvement in braking even compared to the stock 10.98" rotors. When I upgraded my Challenger I even kept the smaller piston original calipers, and it was still a noticeable difference. The later calipers that went with the 11.75" disks on the B/R bodies have a larger piston. Not a little larger either, it's almost a 1/2" difference in the bore.
Not to mention if he's looking to do any significant amount of autoX'ing, he should be looking for performance tires, which means 17" or larger if he's looking for something DOT legal he can still drive on the street between races. And that will make the SBP deal even more inconvenient. There are SBP 17/18" rims out there, but there's only a couple of choices.
