Power Steering for RZR 900XP? Best aftermarket unit? UniSteer, EZ Steer or Other?

Hey guys. My buddy owns a 2011 900XP and it tired of fighting the steering wheel. He is ready to install a power steering unit. He has been looking at Uni-Steer for around $600 and EZ Steer also which runs about $750. Does anyone have these units? Opinions?

Are there better units out there? If so, what and how much?

Thanks.