Hello Mate. I was very lucky, I got them off ebay from a guy who was running them on a vw. He bought four front from Porsche 6-7 years ago. They were pretty knackered and I spent a few days refurbing them. If you want to run original size rears you will have to put a big stretch on some incorrectly sized tyres for the rims (10j!) and have arch work done, and run spacers.......Not really worth it. Get hold of four fronts on ebay (they usually go in pairs from time to time). The diff dosnt recognise width so different size tyres/spacing (width only) will not be a problem. The diff only recognises rolling circumference(i.e. 17' 18' etc). If you did choose to run original sizes as long as the wheels are the same size it will be ok, as long as all four are 17" 18" etc.