We also offer a 200 watt amp for budget minded systems. Both configurations have preformed very well and haven't had any issues in the RZR. You obviouslly are not familiar with audio but those ratings are Peak, not RMS and don't actually 500 watts. They're not 35w lights consuming 35watts. Plus, they're driving a pair of 6x9's, not a pair of 15" woofers so the amp hour draw is WAY less then a woofer based SPL system.

Your kit uses 2 20watt (thats peak) amps. So, your putting out about 8-10watts RMS then. Thats less then half of a typical aftermarket car cd stereo player.....