5th Generation (1997-2001)
205/50/15 - Better Acceleration, Overall Diameter is Smaller
205/55/15 - Recommended 15" Size Tire w/ 6.5" wide wheel
215/50/15 - Larger Contact Patch, Better Acceleration, Overall Diameter is Smaller
225/45/15 - Even Larger Contact Patch, Minimum of 7" wide wheel is recommended, Overall Diameter is Smaller
225/50/15 - Even Larger Contact Patch, Minimum of 7" wide wheel is Recommended
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205/50/16 - Stock Size, Recommended 16" Size Tire
215/45/16 - Larger Contact Patch
215/50/16 - Larger Contact Patch, Overall Diameter is Larger
225/45/16 - Even Larger Contact Patch, Minimum of 7" wide wheel is Recommended
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215/40/17 - Larger Contact Patch, Recommended 17" Size Tire
215/45/17 - Larger Contact Patch, Overall Diameter is Larger
225/40/17 - Even Larger Contact Patch, Very Limited Selection of Brands
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215/35/18 - Larger Contact Patch, Small Profile means Less Protection for Wheels
215/40/18 - Larger Contact Patch, Overall Diameter is Larger
225/35/18 - Even Larger Contact Patch, Recommended tire size for 18x7.5" with at least a +48mm offset
225/40/18 - Even Larger Contact Patch, Overall Diameter is Larger, Not Recommended if car is Lowered
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215/35/19 - Large contact patch, recommended 19" tyre
(Try as I might, I've not found anybody running any other size without drama)
4th Generation (1992-1996)
205/55/15 - Stock Size, Recommended 15" Size Tire
205/50/15 - Better Acceleration, Overall Diameter is Smaller
215/50/15 - Larger Contact Patch, Better Acceleration, Overall Diameter is Smaller
225/45/15 - Even Larger Contact Patch, Minimum of 7" wide wheel is recommended, Overall Diameter is Smaller
225/50/15 - Even Larger Contact Patch, Minimum of 7" wide wheel is Recommended
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205/50/16 - Recommended 16" Size Tire
215/45/16 - Larger Contact Patch
215/50/16 - Larger Contact Patch, Overall Diameter is Larger
225/45/16 - Even Larger Contact Patch, Minimum of 7" wide wheel is Recommended
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205/40/17 - Overall Diameter is Smaller, Not Recommended w/ 7.5" wide or larger wheel
215/40/17 - Larger Contact Patch, Recommended 17" Size Tire
215/45/17 - Larger Contact Patch, Overall Diameter is Larger
225/40/17 - Even Larger Contact Patch, Very Limited Selection of Brands
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215/35/18 - Larger Contact Patch, Small Profile means Less Protection for Wheels
215/40/18 - Larger Contact Patch, Overall Diameter is Larger
225/35/18 - Even Larger Contact Patch, Recommended tire size for 18x7.5" with at least a +48mm offset
225/40/18 - Even Larger Contact Patch, Overall Diameter is Larger, Not Recommended if car is Lowered
3rd Generation (1988-1991)
195/60/14 - Stock Size
205/55/14 - Larger Contact Patch, Overall Diameter is Smaller
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205/50/15 - Larger Contact Patch
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215/45/16 - Even Larger Contact Patch, Overall Diameter is Larger
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205/40/17 - Larger Contact Patch
Offset
4th & 5th Gen. Stock = 6.5" Wide Wheel w/ +55mm
3rd Generation Stock = 5.5" Wide Wheel w/ +45mm
6.5" Wide Wheels w/ 4th & 5th Gen
Less than +38mm ::: You take the chance of rubbing the outside lip of the wheel well.
+38mm to +55mm ::: You shouldn't have any problems. Recommended Offsets for 6.5" Wide Wheels.
Larger than +55mm ::: You take the chance of rubbing the inside lining of the wheel well.
7" Wide Wheels w/ 4th & 5th Gen
Less than +38mm ::: Not Recommended
+38mm to +41mm ::: Not Recommended if you are, or plan to be, lowered. You take the chance of rubbing the outside lip of the wheel well.
+42mm to +44mm ::: This is a grey area if you are lowered, results vary depending on tire and/or drop. You take the chance of rubbing the outside lip of the wheel well.
+45mm to +50mm ::: You shouldn't have any problems. Recommended Offsets for 7" Wide Wheels.
Larger than +51mm ::: Not Recommend. You take the chance of rubbing the inside lining of the wheel well.
7.5" Wide Wheels w/ 4th & 5th Gen
Less than +40mm ::: Not Recommended
+40mm to +43mm ::: Not Recommended if you are, or plan to be, lowered. You take the chance of rubbing the outside lip of the wheel well. Wouldn't recommend using any tire with an overall diameter larger than stock and/or with a tire width larger than 215.
+44mm to +47mm ::: This is a grey area if you are lowered, results vary depending on tire and/or drop. You take the chance of rubbing the outside lip of the wheel well. Wouldn't recommend using a tire with an overall diameter more than slightly larger than stock, you chances of rubbing increase.
+48mm to +52mm ::: You shouldn't have any problems. Recommended Offsets for 7.5" Wide Wheels.
Larger than +53mm ::: Not Recommend. You take the chance of rubbing the inside lining of the wheel well.
8" Wide Wheels w/ 4th & 5th Gen
Some have had success with offset of +45, but not many ::: Tyre size is very dependant on whether or not this will work.
If unsure, use the offset calculator. --->
http://www.1010tires.com/WheelOffsetCalculator.asp" onclick="window.open(this.href);return false;
Stock Bolt Pattern
5th Generation ::: 5x114.3 (some vehicles delivered in Australia, Europe and the Middle East among other places were fitted with 4x114.3 hubs)
4th Generation ::: 4x114.3
3rd Generation ::: 4x100
Will it throw my speedo out?
circumference = pi*d
circumference = pi*(wheel diameter in inches*0.0254+2*tyre width in mm*aspect ratio/100000)
circumference = pi*(16*0.0254+2*205*50/100000)
circumference = 1.921 m
Then work out the new circumference, devide old by new, multiply by 100 and that is your actual speed at the indicated speed of 100km/h (then convert to imperial, since I'm not sure if the forumla works in feet/miles)
Or use this --->
http://www.miata.net/garage/tirecalc.html" onclick="window.open(this.href);return false;
Wanna see some different wheels on your car? Try these
http://www.discounttiredirect.com/direct/interactive.do" onclick="window.open(this.href);return false;
http://www.bobjane.com.au/Wheels/VirtualWheels.asp" onclick="window.open(this.href);return false;
]
(paldies woo par linku 
) 
