I have em on mine, and they work DAMN good. i have the 11 3/4 kit on mine. They will fit in a 15x4 even though they tell you they won't. Install is easy even though the instructions are completely wrong about a couple things. Weight loss with the pro street vented rotor kit is ~25#, most of that rotating. Solid rotors would weigh much less.
Pros:
weight, work good, has dust seals, fixed 4 piston calipers, real trick looking, fair price.
Cons: Had to slightly grind rotor edge with a grinder and flapper wheel because it was contacting rotor (maybe .002-.004). Not a big deal.
Have to permanently modify spindles, but they are a dime a dozen and will never go back.
Pedal feel kinda sucks with powermaster. But they work good. Just feels weird to have a lot of deceleration with little pedal effort. I am used to it though and it does not bother me.
Wheels will be moved out about .5". But if you are running skinny's, it looks about right.