I'll try to answer a few questions as best as I can. Here goes...
First off, these are NOT carbon fiber rotors & pads. The friction material on both sides is 100% carbon, very expensive and takes months to produce. The rotors start out as Genuine Toyota rotors, then have a channel or groove machined about .250" deep around the complete surface (both sides) and almost the complete width of the rotor. After this groove is cut into the rotor, the carbon material is then inlayed into the rotor. The pads are
being produced using a brand new backing plate, cutting another section out similar to the rotors, and setting the friction material down into the backing plate (stock size) to prevent shearing the top of the pad off. Using this process, the brakes will be carbon on carbon. Not as high tech as F1, but not $10,000 either.
As for the rear brakes...why? The fronts do about 70% of the work. IF these work as planned, and IF they ever make it to the retail market, the manufacturer might consider a rear setup.
I don't know.
Coefficient of friction? Who knows, but I can guarantee it will be better than anything on the market. Testing will tell. Think about it for a minute, Formula 1 and World Endurance Sports Cars to name a few, use carbon/carbon brakes.
Weight compared to stock? Probably a little less because of the 4 surfaces that were machined in the rotors to accept the friction material. But I wouldn't expect much.
What else? Oh yea...heat. Most iron rotors might go to about 1500 Degrees Farenheit in extreme conditions, where carbon brakes should max at 4000. But you could never get them that hot. Any car with carbon/carbon brakes must have a properly designed brake cooling system.
Brake life? Good question...only testing will tell.
Jeff