Here is a quick write up on a first gen. First I looked under the hood/firewall to determine where to run the power wire to the battery. I used a BOSS kit from Amazon
for installing an AMP.
Powered Sub - it looks dusty since I was wearing latex gloves
Inspecting the battery/engine bay
Noticed this unused firewall plug on my 03 - look in this area for a 1" unused firewall plug. Drilled a hole to poke the power wire through (I removed the plug to drill)
Test fitting power wire
Fuse in place - used double sided tape instead of supplied self tapping screws.
Removed door to carpet trim pieces - they were secured with phillips screws. Be careful removing - I broke one of the tabs that secures the covers to the cab floor. Quick generic part from autostore to fix it (no pictures - you cant tell now anyway).
Under dash views - I secured my power, remote turn on and rca cables to the parking brake sleeve with zip ties. (second pic below) - also shows where the power wire pokes through the firewall.
Kick panel wiring views
Wiring views under the carpet
Amp wiring - this is behind the drivers side rear seat of a 2003 dbl cab. Grounded to the rear seat bolt.
Amp sitting unsecured behind the seat. I finally secured the amp with Industrial velcro strips from Lowes
- 2" wide strips - no pic. It fits perfectly in my opinion and I am 97% sure it doesn't touch the seat back at all - very hard to confirm in a first gen - not enough room to get my arm back there to confirm in the center of the seat back. For sure it doesn't touch the edges. Also the seat back has an indention that allows the sub to fit into - almost like it was made for it.
Mounted my remote bass adjustment dial just in front of the shifter.
Due to my headunit (Kenwood KDC-X995) and RCA cables hitting something under the dash - I had to buy rt angle RCA adapters.
Very impressed with the sub. Rounds out my aftermarket headunit and stock speakers very well. Install took about 4 hours - but I was in no rush.