Okay, found a bit of time today, and as above I can confirm that they do not fit .. Well to be more specific, the front discs and calipers 100% fit, I have them on the car sitting pretty. They obviously require the brake shield to be removed, but that's quite easy with the aid of a trusty angle grinder.
The rears are the problem. The distance between the mounts on the hub is roughly 1" closer together than the distance on the UK Supra caliper... Absolutely bloody fantastic! After spending £150 on rear calipers, £170 on rear discs, and £65 on pads I was pretty chuffed to find that out :tsktsk: ..
Oh well, I'm not giving up that easily, and I'll be chopping stuff up and making brackets tomorrow to see if I can get them to fit in a safe way. Unfortunately that means that unless your particularly handy with fabrication, the answer is: Fronts = yep no problem, Rears = nope I'm afraid not.