I think it'll be safe to say, if you stick with the better brands, just take note of the Watt RMS rating. Most of the Watt ratings printed largely on the amp/sub itself could most probably be MAX PMPO and not RMS.

As for a matching amp, for example, if you have a sub that's about 100WRMS, try getting a 150WRMS or 200WRMS per channel amp to pair with it but you have to be mindful of the correct gain settings.

Personally though, if your HU only has a pair of RCA outputs, you would be better off upgrading to a 2-channel amp with a pair of decent ready-matched component set, or if your budget permits, get a 4-channel amp, a pair of components, and a subwoofer.

If you still ain't satisfied down the road, then only you upgrade your HU with at least 2-pairs of RCA outputs for better control of fader or crossover settings.

Personally, I would always say if you gonna upgrade HU, at least get a decent one with at least 2-pairs of HU or you'll spend more down the road. Like the saying goes "The Poor Man Pays Twice"

This post has been edited by GRexer: Jan 7 2012, 01:58 PM