Before you let go of your hard earned, have a look at Amurai's wheel comparison thread over on AF1.
He actually weighs (pictures of wheels on digital scales included) front & rears, to eliminate the manufacturers ********, and then goes on to evaluate virtually every wheel available for the Ape. Well worth a look.
Also, the guy is one of the most respected Aprilia tech's in the US. What he doesn't know about these bikes isn't worth knowing.