I wouldn't be concerned with the sony meeting output spec, but I'd be more concerned with reliability. Based on the prices, I'd buy the sony, but I woulnd't expect either to be along term investment.

Hell, I'd go on eBay and try to pick up an old Punch 60ix or a PPI A100 before I'd buy either of those, but that's me. I like old school gear.

I'd say go for the cheaper one (sony) knowing that it may or may not crap out....anything will be significantly better then the "amplifier" in the headunit.

Hope that helps.