HawaiiTitan, I think motoman139 is right about the sizes that you suggested -way too short w/o a major drop, but I found several options that will work.
Tire Size Comparison - too short:
Specification Sidewall Radius Diameter Circumference Revs/Mile Difference:
285/70-17 _ 7.9in __ 16.4in _ 32.7in __102.8in ____ 617/mi _ 0.0%
255/55-17 _ 5.5in __ 14.0in _ 28.0in __ 88.1in ____ 719/mi _ -14.3%
295/35-18 _ 4.1in __ 13.1in _ 26.1in __ 82.1in ____ 772/mi _ -20.1%
TireRack.com has a couple of 285/60/17 street truck tires that seem like a better fit - a Yokohama AVS S/T and a Kumho ECSTA STX
285/60-17 _ 6.7in __ 15.2in _ 30.5in __ 95.7in ____ 662/mi _ -6.9%
These are still 2" shorter that stock. Below are better options but you will need new rims for them.
If you really want the
BFGoodrich g-Force T/A KDW 2 I think you should consider going with 20" rims. An almost perfect size match and not too wide is the 305/50-20, 285/50-20, or the 18-inch 285/60-18, while not as wide as the 305, would be a cheaper option.
Tire Size Comparison
Specification Sidewall Radius Diameter Circumference Revs/Mile Difference:
285/70-17 _ 7.9in __ 16.4in _ 32.7in __102.8in ____ 617/mi _ 0.0%
285/55-20 _ 6.2in __ 16.2in _ 32.3in __101.6in ____ 624/mi _ -1.1%
305/50-20 _ 6.0in __ 16.0in _ 32.0in __100.6in ____ 630/mi _ -2.1%
285/60-18 _ 6.7in __ 15.7in _ 31.5in __98.8in _____ 641/mi _ -3.8%
Now since you would need to buy some 20" rims, here is a link to a bunch of other tires, (some cheaper), in the
305/50-20 tire size, at TireRack, or for the 18" rims:
285/60-18 tires at tire rack
Calculations from:
http://www.miata.net/garage/tirecalc.html
.