The performance gain is from a larger rotor. Most all of the Wilwood calipers are actually smaller piston area except for the really big and expensive versions. I swapped to 14" rotors and Wilwood DP6A calipers and I have great brakes with manual setup on 43's. That said, even the dp6a 6 piston has smaller piston area than the single piston 3/4 ton. Youll have better pad options though and even just a few hundreths mu increase can give you 10% better braking. The key is to understand hydraulic laws. I'd suggest reading over billavistas brake bible for a better in depth understanding.
For me, my manual brakes sucked no matter what I did (chevy 1 ton, chevy jb6/jb7 3/4 ton) until I went 14" rotors and dp6a calipers. Now it's all good! And another thing. Wide open designs sells the bracket to fit 14" spidertrax/Wilwood DP4 or DP6 for a D60. This sllows the spidertrax rotors to slip over the hub and just needs a little turned on the hub outer OD to make it all work. It's a sweet setup!
