Okay, I've been posting a lot in the other stereo thread but I wanted to create a thread based on my own experience because I feel like I encoutered unique scenarios that may help people with their own installs.
I guess I'll go ahead and start with the head unit, which is what I installed first. I went ahead and installed a double din unit in a JK w/the non-infinity system. Taking the center dash panels off is a breeze as long as you are following along with the Crutchfield Master Sheet. Don't make the mistake I (i.e. my brother) did and pry too hard with a screw driver to pop the middle panel off, other wise you will ding up the soft plastic along the edges. I now have a few ding marks that are noticeable, but hardly the end of the world.
Anyways, once you have the entire front section of the dash popped off and the old head unit pulled out you have to remove the metal mounting bracket in the back of the dash. This is the hardest part of the install. Keep in mind you may not have to remove this bracket if you are installing a single din unit.
I went ahead and followed the directions according to crutchfield and unbolted it, but CF's master sheet forgot to inform me there are 3 large plastic screws that must be yanked out of the bottom of the bracket with some pliers. Even after the bracket was completely free in the dash cavity, it would not come straight out. I had to cut it in half with a sawzall and then mangle it up by bending the edges down with a pair of pliers. My hands were busted up pretty good the next day from this.
Once the bracket is out, you can go ahead and install the new stereo. Make sure you have all the wires correctly crimped/soldered with the two harnesses you are using. It is an extremely tight fit to jam everything back there with a double din unit. Push all the wires to the left as much as possible and push the antenna wire to the right and start jamming the unit back there.
Keep in mind , the dash kit for my head unit didn't come with screws, so when i used my own screws the first time, the heads were too large on them that head unit became too wide to fit in the stereo cavity. So I recommend using flat headed screws for maximum clearance so you don't have to make a last minute run to home depot.
Once you get everything jammed in there, you can start bolting everything back up. Make sure the head unit is nice and flush with the dash. This can require some tightening/loosing of bolts to make it look right.
Lastly, you need to add the top dash panel (with the compass attached underneath). Well go figure, my head unit was just tall enough that the the top dash panel wouldn't snap back in place. I was pissed off because i thought i was going to have to disconnect and remove the compass alltogether to make the top panel fit. If you run into this problem, simply unscrew the compass from the bottom of the panel and you will notice some plastic tabs on the bottom of the top panel that can be broken off/filed down. Once you position the compass on the left portion of the head unit and file down one of these plastic tabs, you are able to get the top dash piece to fit back on.
This should have been a relatively simple process, but because of that metal bracket and a couple other snafus, my installation became an all day event.
Here are some pics of the final installation:
As far as the speakers go, the drivers side dash are a royal PITA to install. I suggest starting here, as this speaker can take several hours to replace.
Once you have everything taken apart according to CF's master sheet (which includes removing many hard to reach bolts in tight places), you have to wiggle the speaker box out of the dash cavity. This is a royal pain. Its easiest if you depress the clutch and brake pedal once you have worked the speaker box out of the cavity. It should pop out of the bottom by the pedals if done properly. Putting it back in is a bit easier once you have the hang of it.
The passengers side took all of 20 minutes and is 100x easier to install than the drivers side. You literally remove two pieces of trim and the glove box and have extremely easy access to remove the speaker box making this install very easy.
The speaker bar install is very easy as well. These should only take an hour or so to install both. You just unbolt the speaker grill, remove the old speaker, connect new speaker, and bolt up new speaker.
I recommend buying speaker adapters for the speaker bar because most speakers are not a direct fit and it would be a pain to not have some sort of adapter.
Once everything is all hooked up, you will notice an amazing difference in sound compared to the stock speakers/head unit. I recommend stuffing the speaker bar and speaker pods with polyfil (thanks mr. sinister) as it makes the speakers operate like they are in a bigger box than they are.
I did my complete install for $350 and the results are awesome.