Yeah it took me about 3 days to do my wiring with all the confusion. If u do it on your own, make a wiring diagram with the changes so u can use it as a reference.

http://car-part.com/
try searching for a dealer near u. Or get it shipped from somewhere but make sure they ship the taco 5spd not 4runner cause they did that to me and I was confused cause the wirin didnt match the diagram.

No adapter is needed, the 3.0 5spd bolts right up to the 3.4 engine. the wiring for the five speed is simple. there are only a couple of small plugs. I would highly recommend getting a wiring harness from a 5spd Taco for the same year as the ecu that u have. The plugs may be the same but the wires may be in a different location within the plug. U may wanna look at a wiring diagram for that year Taco to make sure the wires r in the same spot for each plug.

Are u gonna wire it up yourself or get 1 made? You will need to get an engine wiring harness for a 96 Tacoma also. Dont get a 4runner's harness or a different year Tacoma cause there will be different connectors.If doing it yourself download a wiring diagram for that year 3.4 and your truck's year. I recommend going to toyota's tech site and paying the $10 for 24hr and downloading everything. Do you havea manual tranny already? If so then you can use your old tranny, just get the 3.4 flywheel, pilot bearing, and clutch but use the 3.0 throw out bearing. everything bolts right up. The hardest part is the wiring, just tedious. hit me back if I can be more helpful.