True ,
i might just get 4 but not just yet dont wanna keep wasting money ....
I think this depends upon your 4 wheel drive system. My S3 drives the front 2 wheels normally and then puts power to the rear when the fronts slip, so it's not permanent 4 wheel and so you can change 2 at a time. Recommendation would be that the new tyres go on the rear.
My wife's TT is permanent 4 wheel drive and there is a mm limit difference between front and rears that means she generally needs to replace all 4 at the same time.
Roy.