I'm going to be running a single 12" kicker solobaric L7 sub with the amp.
I found a used JL Audio 500/1 amp for $250, which is about the same price as a new KX600.1. I know the JL amps are underrated, but which would be a better choice given the used vs. new argument.....are the JL amps really THAT much better? $250 sounds like a pretty good deal for a $700 amp.
Also, would a 600W RMS 2-channel amp work with that sub at all? I'm not sure how that would be wired if it did...
Yes JL Amps are that good If you can get one for that cheap I would go for it just make sure you can return the amp if its broken.Sound Quality will be improved with the JL amp over the Kicker Amp although Square subs do not always sound good but hit really hard.