I've tested JY, Limitless, Extreme, and XS lithiums..
It's pretty obvious the poster above has some kind of wiring issue. 3 alts with a 100ah is more than enough for the little amount of power he has. I have a Limitless 70ah (3 alts) on 20k (clamped) with no problems and voltage in the high 12s.. JY has batter performance this year with their black box that upgrades inductance rails and limitless has also upped their output on all models as well as making them smaller and more durable.
I'd go limitless because they have more output than the JY. The only reason I didnt like JY was the ugly green box, other than that a solid performer but not as well as limitless. (limitless is the leader in aftermarket lithium for bass)
XS lithium is complete crap, same with Extreme lithium. They are full of foam and substandard parts. They look like they were thrown together by a 10 year old and NO ONE uses them.