I would say yes. I really dislike the fact that the Wilwoods don't have seals, although I heard that the more recent 4 piston calipers do have them. Don't own a set so I don't know. I recently pulled an old set of wilwood 4 piston calipers off a buddies car that had seized up pistons. Now, those were older design wilwoods that definitely did not have seals, and that car had sat for awhile before my buddy got it. But those things were complete trash.
So, just because the pistons are stainless doesn't mean they can't have problems. Dirt and junk getting into the caliper past the pistons is still bad, and you can still seize a stainless piston in an aluminum caliper.
Your #1 option should be more like $740, since you already have the spindles you need. And that would make it the same option as #3 really.
For me it would be #2 or #4. Check to see if you have the larger piston calipers already though first.
That's a different kit. The DoctorDiff 2+ kit uses factory 11.75" rotors, not a wilwood rotor and hub. So it's factory disks with a custom caliper bracket that allows the use of the wilwood caliper on the mopar rotors. No worries on the gigantic wilwood hub in this case.
Is it possible? Yeah maybe. I can tell you the factory 2.75" calipers generate more clamp force than the 4 piston wilwoods do by the math. But it's not really a good comparison, because the single piston floating calipers will lose a lot more of that generated force because of flex, uneven application of the force across the pads, etc. than the multi-piston fixed calipers will. So I would say that in this case the wilwoods would likely perform better as long as they're functioning properly. Having said that, I've seen the wilwoods seize up. And I've seen the factory calipers work with some ungodly looking sludge for brake fluid. I would bet that the wilwood calipers would give you better braking with everything in new condition, but I don't know if in your application it would really be worth the extra money.
