Jl's are expensive. But they are worth every penny. They are very versatile and will work well with just about any kind of enclosure, assuming it's sized right. They hit very hard and very clean at the same time.
The 6's are 6 ohm speakers and are designed to be used either singly, or in triples, to work with most amps. You probably don't have room to run 3 12's unless you don't ever use your rear seat. If you are really interested in JL's in your jeep, look at their stealthbox. It replaces your center console and has a JL 12 built into it. It looks stock, completely unnoticeable, which keeps your sub safe. It also sounds great even with a soft-top, and it even hits hard with the top down.
It is kind of expensive, but if you keep replacing subs and slashed soft-tops...