The offset for GTI wheels is 51mm so I cannot see that 45mm would be suitable. Getting the offset correct is critical to steering and handling of your car. Such a big difference from standard would mean the wheels would not sit correctly in the arches.
I am not an expert but thats my opinion. People selling you stuff from Ebay will always swear that things are perfect to get their sale. When you find its unsuitable they are generally not so accomodating and you have wasted a pile of cash.
I do not really have much experience of winter tyres except for years ago I got a set for my Fiesta as I wanted a cheap set of tyres for a while. They were awful, rock hard so really noisy and no grip on the corners. Could you not just go for ordinary tyres or do you live somewhere really snowy?
