tires

I have a new v.s. with the stock wheel/ tire combo. i happen to have a spare set of 205/50/15's in my basement. has anyone ever found these to work without mod's, or should i just pony up and order the 185/65/15's?

This site might be of help to you guys www.miata.net/garage/tirecalc.html , it will show the difference in sizes from one tire to another. And just a note for those who dont know, the numbers (205-50-15) on a tire mean that the tread width is 205 mm (or 20.5 cm), the side wall is 50% of the width (20.5 * .5 = 10.25), and the rim size is 15 inches. So from all this info, your 205's will actually have a smaller outside diameter but will be 20 mm wider. if you have more then 1cm (20mm/2) of clearance from the tire to the body, you should be fine. What I can't tell you is if your rims can take a tire that much wider.

George, I doubt that the 205's will fit in the rear. I've seen a few IMs with 205s in the back, but that was using IMs seven inch wide wheels, with a very negative offset. I've even come across one IM with 215's on the back, but the clearance was paper thin (literally). Also, most replicas have less clearance on one side than the other, so when you're fitting tires make sure you try both sides. It really depends on how wide your rear wheel is and what its offset is. Fitting for the front doesn't usually cause any problems.
An excellent size, if the tire will fit, is a 195/60 x 15. The diameter is only about .2" less, when compared to a 185/65 x 15 (24.2 vs 24.4). The trick, of course, is to get them to fit. Some people have even had trouble fitting 185's. Again, it depends on your wheel width and offset.
Ron