If you want detailed information, try these links. Or search google for "the meaning of ohms"
Wiring Subwoofers — What's all this about Ohms?
how does ohms work? [Archive] - Sweetwater Forums
If you want a simplified explanation, just get speakers that match the impedance of your amp. 2ohm speakers=2ohms amp. 4ohm speakers=4ohm amp.
Most of the best amps are 4ohm amps. Most of the best speakers are 4ohm speakers.
Don't mix 4ohm speakers and 2ohm speakers. Mixing ohms can burn up or overheat your amp. It will also sound horribly unbalanced because 2ohms speakers use half the power of 4ohm speakers.
If you want power, try throwing in a Alpine PDX-V9(100wattsx4@4ohms +500watts sub), and build your system around it. If you do, you'll have a great powerful audio system.
But, you will probably need to switch out those Infinity Speakers. Medium to Entry level Infinity Speakers are generally not High Capacity Speakers(40-55wattsRMS). I doubt your Jeep spec says anything about the power output of the amp or the handling capacity of the speakers. So, you'll want speakers that are rated around 100wattsRMS. CDT's are great, medium cost, high capacity speakers, when running a subwoofer(90-150wattsRMS). When not running a subwoofer, they may lack in bass output. If you have separate tweeter and midrange/bass speakers, then you'll want component speakers and not coaxial speakers. The CDT's come in convertible speakers, so they can be mounted as coaxials or components.
Easy Way Electronics CDT Web Shop Home Page
You can find a good subwoofer setup with downfiring subs here. This is what you want for "Top off" situations. 500watts of power from downfiring 2-10" subs, in a low profile box to save space. You can also request the seller for a different subwoofer manufacturer in the box, such as MTX or Kicker. But the Helix are rated for 500wattsRMS.
07 13 Jeep Wrangler 4 Door Custom Sub Woofer Box Loaded 2 Helix Audio B10 Subs | eBay
Anyone is welcomed to correct me if I am wrong. I am just trying to help, and I don't claim perfection.