I've had to bring both down from freeway speeds (well, 75 or so). I think the four piston, when right are better, but not enough to negate the wheel choice options and overall cost. With that said, we have late discs on my sons' big block/four speed a-bodies and we've also had K-H discs on my son's 383/4sp autocrosser Barracuda and other cars. They both work well.

I know this sounds like I'm not definite, but my reasoning for the late model discs was strictly for wheel choice. If it was easy to go 4.5" pattern on the K-H rotors, then all my cars would have them......