Yup. It has a replacement HU already (JVC)... I'm not exactly all that sold on it though, so, I have choices, use my unused Kenwood KDC-X994 and suck it up that HDRadio and Satellite (Sirius Ready, not Sirius XM) is going to be a pain and on the expensive side, or get a different HU.... Maybe the DDX-774BH or the new DDX-775BH... (Excelon is nice, but starting to wonder if it's really worth it in the newer models. Kenwood still has a nice and sensitive FM tuner section, more so than Pioneer and most Android HUs. I'll stick with bluetooth in the HU for streaming and hands free calls (as noisy as they might get.) (yeah, I might be splitting hairs between JVC and Kenwood since they are the same company now, but I like Kenwood better.)
Door/pillar and rear panel speakers I think are pretty much set now and I'm still leaning toward a Rockford shallow mount Punch sub, although Kicker and Pioneer isn't 100% eliminated. I'll probably wire for the 2 Ohm load on the amp I'm considering to max out power there, using 60x4 @ 4 for the front and back, and 350x1 @ 2 for the sub.
The Power amp choice is what I'm most concerned about as the Soundstream Picasso Nano PN5.640D is the one I'm looking at. Power out is good enough for me, but it's quality that I'm not settled on. (the price is nice though.) I do plan on keeping it in the same area as the original Monsoon amp and probably running new wires out. (unless someone tells me the OEM wiring should be fine for my power scale - 60Wx4 with the Sub channel being more, and a shorter run.) Now I do know the original Monsoon amp has a 20A fuse, and the Soundstream has a 40A. (new power wiring would have a 50A or 60A near the battery.)... which leads to if I want to max out the power, if my 125A alternator will suffice. or should I find a 145A or slightly more, model.
it's better to change my mind like crazy now than after I start purchasing and installing the various parts.
Thank you all who have chimed in so far. (response time over at CarAudio.com so far hasn't even been close.)