Ive got a willams in my garage at the moment, number 151 on an L plate, i also have a 205 1.9 gti, 106 gti, 306 gti6, 309 gti and a 206 gti (too many cars i know) the rear calipers are the same on them all, the caliper yokes and pads are different on the williams, the pug calipers dont have the retaining screws for the outer pad.