Just a comment here ... a friend had one a long time ago and I believe that he struggled to source the correct size tyre as these particular wheels are a strange size.
Perhaps you should consider changing the wheels to something similar in design (still an OEM wheel though) but perhaps in 17 to make your future tyre purchases a bit easier and perhaps cheaper too.
I may be smoking my socks but I am like 80% sure that this is the case ... please correct me if I am wrong.