welcome to the site mate
what are you wanting ?
off the top of my head you should have 232 x 9mm solid discs on the FWD or 256 x ##mm vented on the quattros
problem is you cant fit the quattro parts onto the FWD due to the different suspension setups.
however you can look to the skoda VRS or post 2003 - 2005 Mk4 Golfs and boras which should have the 256mm rears and different callipers.
the 4motion (it really isnt a true quattro) can be made to fit by using i belive a 6m spacer to space out the calliper
there is also a 284mm disc upgrade from the 256
what have you done up front regarding braking ?