Changing wheels/tires any guess on the mpg gains?

[therealtime]

I am currently running stock del Sol Si wheels with 195/60/14 tires.
Average weight of a 195/60/14 tire is 18.3lb (calculated from tire rack tire weights). The del Sol wheel weighs 15lb.

Total unsprung rotating weight per wheel is 33.3lb.

I am hoping to snag a set of Civic VX wheels with 175/70/13 tires.
Average weight of a 175/70/13 tire is 14.8lb and the VX wheel weighs in at 9.7lb.

Total unsprung rotating weight per wheel would be 24.5lb (reduction of 26.4% or 8.8lb per wheel, 35.2 total)

The vehicle velocity would also change by reducing tire circumference by about 2.5% (my speedometer is currently 2.1% too slow because my tires are larger than stock and the vx tires would make it 0.4% too fast)

The frontal area would be reduced because the car would sit 0.3 inches lower and each tire is 0.8 inches narrower.

seems pretty dramatic to me when you combine the reduced area, reduced resistance to rotation and reduced total mass. the only drawback is the smaller circumference which would make the engine run at higher rpms (81 more rpms to maintain 70mph).

any educated guesses as to the mpg gains to be found?

thanks,
-tony