will these tires rub?
Your bigger issue will be whether it screws up your speedometer and messes with your electrical systems. IE, traction control worries about # of revolutions and/or angular velocity of the wheels. You don't want the front/back to have different diameters. Could also cause an issue with cruise control. if all 4 are the same, its less of a problem. Speedo will be off if your tire size changes.
http://www.miata.net/garage/tirecalc.html good reference for tire size adjustments


