plenty of guys on here have warp9 wheels. i personally (from the quality i've seen here in Aust) wouldn't touch them. i've had a few customers buy warp9 motard sets off ebay for local race classes. all but one have cracked hubs or flogged out the bearing area of the hub within the season.
My preference on the r2 would be OEM r2 hubs laced to 17" SMPro or Excel rims (3.5" front/4.25" rear) with custom spokes. means no brake swapping between wheels, can use standard discs/sprockets, if you want bigger apparently wr250f oversize kits will fit, rims are slightly larger than stock so suit common tyre sizes better.