215/45 R 17 tyres will not fit! Well, they will, but they'll rub.
I went from 205/40 R 17s to 215/40 R 17s on my new wheels after buckling problems on my Sport wheels and I got a set of genuine TT alloys from an Ebay seller (he's got another set up at the moment actually - and the Tank appears in his listing wearing the new boots!).
http://cgi.ebay.co.uk/ws/eBayISAPI....30009630934&rd=1&sspagename=STRK:MEWA:IT&rd=1
The wheels have been great and they were brand new. Very good value at what I paid for them.
Now that they've been on a while, I've had a look for rubbing and found only a tiny amount on the front nearside liner. On partial lock, when the rubber is nearest the liner, I can't fit a finger between the tyre and the liner, so I really would urge caution on the 215/45s.
I have noticed a better ride since changing and it's now up there as one of my 'glad I took the plunge' mods.
BTW - the offset on mine is ET 32 which means that with a 7.5J rim, you keep the same inner clearance.
Cheers,
Mike