thanks all.
PA speakers almost always provide RMS and max power specs, but home audio companies don't list that 'max power' information, just general recs for power requirements, as they don't want to turn anyone away and want to capture as many customers as possible.
My misunderstanding was around the volume control. I had the impression that a speaker rated 50-100w at 4ohm would be incompatible with an amp that puts out 500w at 4ohm. I thought that the speaker still sees the majority of that power even at volume 0 or 1, that the power is just there and the volume control is just controlling volume, not watts.
i understand that overpowering a speaker will first push the woofer to its mechanical limit, tweeters will likely not hit their mechanical or thermal limit. it makes sense that you would be able to hear when you're pushing too hard. but this person on reddit, the way he laid it out this is his first foray into audiophile type gear and i don't know if he'd pay attention to when a speaker is being pushed beyond its limits. and to answer questions above, i asked the same questions to him but got no response (room, space limitations, preferences). i know he said he likes metal, shoe gaze, probably modern rock, etc, so i imagine he's looking for a speaker that can rock out.
i agree with the recommendations above (most $ into speakers, budget dac/preamp combo). not because the amp isn't great (i haven't heard it, but I've read a lot of positive feedback here and on steve hoffman and trust the people that have) but id almost recommend he sell the amp to get into the best speakers he can swing, and minimal into the other components. anywho...