Anyone who even considers putting inferior, part worn or any kind of budget tyre (I.E mixed front and rears) on the rear must be either completely stupid, COMPLETELY stupid or COMPLETELY STUPID.
A front wheel drive car's worse enemy is oversteer, in the extreme there is simply nothing you can do about it but pray you don't hit anything as you swap ends, best case is that you have a pant filling episode of windmilling arms with bucket fulls of opposite lock, (I wont even mention a slight rear end twitch with the adrenalin inducing steering wheel twitch as this just the territory of everyday boy racers, noob drivers, we after all, a forum of enthusiasts and expert drivers lol

)
All VAG cars (and indeed most production cars) are inherently designed to understeer for safety reasons as understeer is relatively easy to detect and prevent against, they do this in order to stop you having to deal with oversteer which lets face it, over 75% of people haven't got a clue
how to deal with.
SO why oh why oh why, when the only thing between nearly 1400kgs and the road is a dubious piece of rubber and the laws of physics would you skimp on that said piece of rubber???
IMHO only someone completely deviod of intelligent reasoning would take that line of reasoning that somehow saving a few pounds WON'T compromise their safety or the integrity of their precious hard earnt machine.
Most of you will sat there thinking, what is this fool on about? But how many of you get your smiles with traffic light grand prix's and the frequent WOT, torque inducing, straight line sprints? 75% of you will not have a clue
how to drive truly quickly point to point through twisties or on a track, This inexperience does not teach you
how to instinctively react and safely overcome an oversteer situation.
Ok, that's in the extreme but my point is this, IF, when you MOST need it, that budget, worn or mismatched piece of rubber is all that stands between you and swapping ends (perhaps just before you hit a wall, a lampost or another car) then your chances of successfully coming out of that situation are already significantly compromised even before the situation occurs!
So if when you come to skimp on those rear tyres you are thinking, "well, it's only the rears, they dont do much" then think again, you may not drive on a track or even push on round the green lanes of this fair land but the one time when you find yourself in an emergency situation and your car steps out unexpectedly or worse then remember my words.