Ok, so I did the following in this order:
- installed Kenwood DDX5706S Head Unit
- installed DynaMat Xtreme on inner and outer door skins - used 36 sq ft to do all four doors (some say there's no benefit to using as much as I did but I like it). This included covering all of the large holes in the inner skin
- installed DynaLiner on the rear doors - bought the 1/4" thick version and it worked but is a little tight to install door panel. I bought enough to do the front doors as well but haven't put it in yet. I think I may order 1/8" for the front and use the extra 1/4" in the cargo area
- speaking of the cargo area, sound deadening the doors made the cargo area noise more apparent, I'll use Dynamat on the outer walls and wheel wells then top with the 1/4" DynaLiner
- installed Morel Maximo Ultra 602 components in the front doors
- installed Morel Maximo Ultra 602 coax's in the back doors
- added Morel MPS 4.400 4 channel amp
- installed Kenwood KSC-PSW8 on floor in cargo area
Result: Sound is really fantastic! I would like to get it tuned properly at some point but in the meantime we are really enjoying it!
Recapping the step by step. By adding the head unit I got the features I wanted as far as Car Play, etc but it did not improve the sound on it's own. Adding the sound deadner and speakers was a definite upgrade but nothing I was excited to listen to. Where the system came alive was when I added the amp and the powered sub. Many including
@suprarx7nut recommended changing out the amp and I was good with that but, in addition to being unsure of the possible wiring challenges, I wanted to see how the factory amp did with everything else new. Well, let me just join the chorus of those saying go ahead and plan for the new amp! The wiring wasn't difficult at all, I just needed to stop reading all the threads here and jump in. Overall, it took a lot of time to install everything but doing it in stages helped and I'm very happy with the result.
I took a number of pictures and plan to add a thread for the sound deadner install as you won't find much here on this board. May also do something on the amp install just to help take a little more of the mystery out for the next guy because it's well worth it.