The standard tyre size (as fitted from factory) is 175/60r15
Which is what is fitted on my mum's SVE ^_^ (same wheels)
If you have a look on willtheyfit.com you might find other sizes that will maintain the rolling radius, possibly 185/55 r15?
I have a sport+ with the standard 11 spoke 16"alloys, running the standard size for those at the moment (185/50 r16)