It depends on how much thump you want.
I'm a huge fan of the Kicker solobaric subs. However - they can produce overkill - Dual 15" Kicker Solobaric L7's, ZX2500.1 in my 2010 4 Door Jeep Wrangler Rubicon, now thats bass. - YouTube

With regards to your other speakers - have you/are you going to upgrade them? Most good aftermarket decks will provide enough watts per channel to provide your other speakers with what they need. Unless you go Big Time with them, you shouldn't need an additional amp.

 

Sorry, I dont know that much about speakers. I currently have 4 Kicker speakers instead of the factory ones. I was hoping to keep the stock head unit though, is that possible? The kickers run at 75 Watt RMS, IDK if this is good or not. With my stock head unit am I getting the best I can out of these already?

 

If you have the 430N or 730N headunit you should be okay, but I'd highly recommend upgrading your headunit. The headunits also have built in limiters so the user wouldn't blow the speakers or sub (if you have one) when they turned up quickly to a higher volume level.

 

In reference to Rockford Fosgate vs JL, Rockford Fosgate subs give you much deeper bass and "heavier" bass for that awesome thump and punch. On the other hand JL provides less of a thump but is a tighter bass and "cleaner" but like I said also a lot less "bass" in the sense its not as deep and heavy. Now when it comes to Rockford and JL speakers, both are great, truly with these companies it becomes more of preference. But you will get more power and a higher power range with Rockford in comparison to JL. And well..... Kicker just doesn't compare... But if you like Kicker and the way they sound then so be it! Just my two cents.

 

So you sugest a better head unit and an amp + subwoofer? What kind of head unit do you suggest?

 

With a headunit it depends whether you like single din or double din headunits. My preference for a both is Alpine, however Pioneer and Kenwood also make good headunits as well.

 

Ok, thanks for the information it will come in handy!

 

No problem! Good luck with whatever you choose!

 

I agree. Alpine makes a great head unit and I think you'd get better sound out of All your speakers with an updated head unit.

With subs, the more people you ask, the more opinions you'll get. I also like Rockford Fosgate a lot. JL's, in my experience, sound dull when there's just one. They tend to come alive though when you run 2 or 3 in a series and drop the ohms down.

 

I run 2 12" Rockford Fosgate P3's wired at 2 ohms with a JX1000D amp going solely to the 2 subs and 1 Farrad capacitor. IT IS ABSOLUTELY AMAZING. I also run 3 way coaxial Rockford speakers for all four speakers, they run at 120RMS. I will soon be putting an amp by Rockford rated at 600 watts that actually pushes 1000 watts straight to all 4 speakers. The Jeep SCREAMS AND SOUNDS INSANELY CLEAR, along with AMAZING BASS.