||07-05-2013 07:50 PM
I'm working on a really similar audio upgrade at the moment. I'm still at the stage of acquiring all the parts before I go to work installing everything. My truck is a 2012 Double Cab, non-JBL, so I believe we have the same audio system.
As jaxadam was saying, the stock head unit is a big limitation, so I've decided to replace it along with the speakers. I want to replace it with another double-din sized head unit, and I'm really not interested in having navigation or DVD playback. From what I've read on this site and others, the JVC KW-R900BT is one of the better sounding head units for the money. It runs about 170 bucks on Amazon.
As for the door speakers, a lot of people seem to really like the Polk Audio DB651s 6.5" coaxials. They run about 60 bucks a pair. Now, some people recommend getting a good set of component speakers for the front stage, but these can get pricey. Also, from what I've read, most people want to add an amplifier to run component speakers, though some people do run them directly off the head unit.
Now as for the dash speakers, I'm still not sure what to do about these. If I get component speakers for the front, then replacing the dash speakers with the tweeters from the component speakers would probably work well. Also, the JL Audio TR350-CXi 3 1/2" coaxials look nice for the dash, but if I don't add an amplifier, then I'm not sure that I would want to run both these and the door speakers off the head unit front channel. The dash speakers and the front door speakers are wired in parallel on our trucks, and if I keep it wired like this, it will drop the impedence down to 2 ohms. I'm not sure if running 2 ohms would hurt the head unit or not.
Anyways, maybe this will give you some ideas. I should probably mention that I'm also adding a small subwoofer to fill in the low range sounds. I decided on a Pioneer TS-SWX251 10" sub. It runs about 125 bucks, but the best part is it comes with a compact enclosure. It should fit right under the rear seat.