adapter for mach460 with 50watt x 4

I have just bought a pioneer head unit for the stang basiclly beacause my stock CD player works only when it wants to. Anyway I don't plan on a building a big system in this car I'm planing to install the head unit with the adapter to power the mids and highs and just run one set of RCA's to a 800w mono sub amp for two 12's.

This a 50 watt per channel head unit and I have been told by questionable "experts" that this is too much for the mach 460 amps to handle and to get a cheaper 30 watts per channel and it will be fine......Is there any truth to this theroy.. I have built many extensive audio and video systems but I just don't feel like tearing the whole car apart to hard wire the speakers......Anyone have any input!!!