BBS RX2's are nice wheels, I used to run them on a Mk3 - but you need to be aware that they are one of the worst OEM wheels for space inside for brakes. On my Mk3 the caliper was only a few mm of the inside of the spokes. I can also report that the RX2's are heavy, a nightmare to clean and it seems their second function in life is to corrode.
If you do go with the R32 calipers, ignoring wheel space, you will need to make custom carriers for the calipers to fit on.
I would stick with the common upgrade retaining the existing calipers and using them with 280 discs and carriers.