Well got the conversion well under way now so i thought I'd put some words and pictures down.
First up, this is for the hub set-up on the 1.9,and i think this is the same up the range apart from the M.
Disk selection is reasonably easy, its just getting the correct offset to caliper distance. I found the best disk for this was the E46 330i as it has the same offset as the 1.9/2.8 set-up.
The 330i disk is 25mm thick and 325mm in diameter, so a good upgrade from standard size disks, i had 2.8i 286mm disks on before but i decided these would not be upto the job with the V8 engine. 325mm seemed a good compromise without going to big.
they bolt straight on and site nice behind an 18" wheel