the things you should look for on a GTS/Alltrac/GT-Four
a bolt pattern of 5x100
and depending on width of wheel
i had 7.5" wide wheels on my car with a 35 offset last year, the front was close to being flush with the fender but the problem with the GTS/Alltrac/GT-Fours is that the rear will need a spacer or wider wheel to fill out the wider fender,
ive heard that with a 7.5" wheel that has 35 offset will need a 20-25mm to be flush,
as for diameter
http://www.miata.net/garage/tirecalc.html
this should help
BTW i noticed that your car is RHD, very nice