I'm in the process of doing a full aftermarket upgrade:
I just finished a full sound deadening: CLD at 25% (Dynamat extreme), 1/8" neoprene CCF, 1/8" MLV on the doors, floors, hatch, cargo, and rear wheelhouse. The roof has CLD and 1" hydrophobic melamine foam. Door seals will have 1/4" silicone tubing inserted.
This far into it, I decided not to do OEM Audio+ nor TacoTunes plug-and-play systems...
JL audio 8" sub in the stock enclosure with custom adapter spacer ring (no cutting or dremeling the enclosure).
Just finished running new wire for the hatch speakers and this week will finish running new wire for the rear doors. Going to use OEM terminals in the door connector to avoid snaking new wire through. This way no more series wired rear speakers!
Putting in Focal speakers all around; 6.5 components (with tweets) up front, 6.5 coaxials in the rear and hatch. Using HD TacoTunes speaker mounts throughout, and TacoTunes under seat amp racks. A JL 8-channel amp to run them all.
Not sure what head unit to go with yet. Looking at Kenwood, Alpine, and Pioneer. Not sure if I'll do a double-DIN or a floating unit.