brakes

Hi,
I?ve heard a lot about the mk2 GTi 16v servo and master cylinder being the best mod for my mk1 GTi cabby. I?ve found someone selling a master cylinder which is 22.2mm (he said the ones that came standard of golf G60s), and the only information I?ve found is that I need a 22mm one, I know 0.2mm is microscopical, but I need to make sure this is the right one, is it?
Also, having a scrapping sound coming from the front passenger side wheel, it sounds with every revolution of the wheel (not constant, it gets faster as the car goes faster) only sounds when in motion. Anyway, I thought it was the wheel scrapping the arch (cos I have 17s, but they only scrape with excessive weight, and also, that would be a constant sound right). But I think it could be something else. After parking it up right now, I noticed the brake disk on the passenger side is a lot hotter than that on the drivers side, so could this be a brake fault? The sound is the same when brakes are applied though, it just slows down as the car gets slower. Please advise.

Have a browse through the braking FAQ plenty of info there.  
You may have a warped disc or a binding caliper by the sounds of it, raise the front of the car and spin the wheel to see how it sounds/feels.

check you brake pads to see if there down to the metal, ive done the 16v master cylinder and servo on my cabby and its made a great difference, i also put on braided brake lines too, its the best upgrade ive done so far!! (apart from the 16v transplant)