Tire pressure isnt a mod- just basic maintenance that does effect MPG for sure. A chip with a controller has given me the best results in other vehicles so I don't see why it wouldnt be the case with a t4r.
Just picked up a '94 with a 5sp, and a 3.4L twin cam from a 99 tacoma. Clean swap- just needed to change battery location and some exhaust work done due to the crossover having to be changed to the driver side. Got K&N intake on it and he dynoed it in front of me and it put out 198hp @4600rpm...