id say get strong rims, and a realiable brand. iv been riding street/park on bmx for the past 4 years now, and now i always go for stonger parts, at the moment im running a Odyssey rear wheelset, with Snafu hub, for extra strength. i dont worry about weight too much in park, as by pumping ramps and that, ur momentum will be the main factor in heightened airing and tricks.