mine , in short , the rears will not have the ajuster rings in at all they will be removed so the rear tyre will sit about an inch into the arch and the front all teh way down
with the ARB from the GTi its welded on to the rear beam so i have been told
as for you upping to the 280mm brakes you wont need the calipers , you just need to replace the caliper carrier on yours to G60 280mm carriers then change the discs