I have the same issue.....
My A4 TDi 130bhp Sport has those aftermarket RS4 alloys (18's) which came with cr4p tyres on (Fortuna I think) I replaced the fronts a while ago now with Toyo Proxies T1-R and I have to say, I am not that impressed with the wet handling, but the one on the rear is diabolical, I have los the rear end in wet conditions going round roundabouts and the such and thats not even pushing it, after reading all your comments, I have decided that I am gonna try x4 new Michelin Pilot Sport PS2's, they are a little on the expensive side but I'm gonna have to go for the best cos i'm driving like i've got Miss Daisy in the back on a wet day paranoid that the rear end it gonna step out any minute.
Has anybody else had any experiences of loosing the rear end in wet conditions, particularly in wet conditions ? (or could it be something else in addition to cr4p tyres like some suspension setup not quite right ?)
Also, anybody know where I can get these tyres from cheaply (less than £140 a corner ?)
Cheers,
Scott