The L5's are a decent mid-grade sub. I have had pretty good luck with them myself. Not a bad choice...
But I do agree with what someone else said, I would be afraid to buy any sub used.
And you can't re-cone Kickers.
But if you buy them new, they are pretty good about replacing them, no questions asked.
Is there any other subs you had in mind?
DC makes some really nice stuff, maybe some lvl 2 or lvl 3 - 12's? Also, AQ, Sundown, and Skar seem to be doing big things too!
And there is always Fi, AA, and DD, they also make quality product, just not sure about the price range.
Anyway hope this helps. Good luck!