if you want to see how other tire sizes match up versus your stock size, you can go here: http://www.miata.net/garage/tirecalc.html
it'll calculate the overall diameters for you and tell you how it would affect your speedometer.

glt, you said a lot of stuff in that last post. one thing is slightly off, though...bigger rims are more for looks and handling and not to lessen the wheel well gap. if anything, bigger rims will highlight the wheel gap. the only way to lessen wheel gap is with lowering.

if any of you are looking for 215/45 tires, or any size, tires.com and tirerack.com have good name brand ones for decent prices. i got 215/45/17 pirellis from discount tire (tires.com) for $116 each that are highly regarded and rated #1 for ultra high performance all season on tirerack.com's user survey. if you need help with choosing a tire, tirerack.com has good reviews and user surveys broken down into performance types. glt, good luck with your rim and tire search. nice wheel choice, akkord.