Just got new front tyres fitted today Goodyear F1 GSD3's. A bit slippy at first but after a few miles they are definitely the business. Loads of grip and the car feels a bit more nimble than before. Anyway, to the point...the guy at the garage asked me if I'd ever had puncture repair foam sprayed into my wheels. I've never heard of the stuff but he said both fronts previously had this and that it can corrode the alloys. Is this something that Audi do? He said that the tyre pressure may start to drop if the rims get too corroded. Sounds a bit dangerous to me.