Hi I've only just seen your message when I was searching the web for info on Mazda Corrosion in general. Hopefully you've got your problem sorted now, but I thought I'd tell you my experiences - they sound very similar! My Mazda6 sport is a 52 plate. After about 3 years I noticed corrosion on the alloys but very stupidly didn't do anything about it as I thought I would get the usual "its not covered by warranty". Then 1 week after the warranty ran out, we were back in the dealership buying another Mazda and I mentioned to the salesman "I hope the wheels dont go the same way as those on the mazda 6". He said I should have brought it back because it was a common problem and that it would have been fixed under warranty. He said that as a goodwill gesture they would most likely still replace them if I wrote and complained. So I wrote to the dealership head office (Arnold Clark.....dont get me started ) and got a rude reply saying that since the car was out of warranty - tough. I wrote again (this was my 4th Mazda I'd bought from them) and got the worst "customer services" letter EVER.....VERY rude, basically saying, dont write again the matter is closed. They claimed that they had contacted Mazda who had refused to do anything about it. So I ditched Arnold Clark and went to Murray Mazda for my next service. I mentioned the matter to them and they said they'd take photos and contact Mazda. Mazda UK came back and offered to pay 75% of the cost of replacing the wheels. Result! So my advice is definately hang in there. We were told that Mazda knew of the problem and it was related to the type of salt used on the roads in the UK. Keep at them and hopefully you'll get something. Unfortunately, I'm now having major probs with corrosion on the rear wheel arches - another prob recognised by Mazda, but fighting now to get it repaired under the anti-perforation warranty. Good luck anyway!