To avoid enthusiast taking a mistaken route:
Internal mods are a proven dead end. Higher compression pistons are not a sound idea at all and porting + Stage 1 cam is both disapointing ánd NEEDS a sports exhaust.
On the 1ZZ-FE reground cams will almost certainly lead to problems with bucket thickness.
The gains from tuning the 1ZZ-FE in n.a. guise are limited, marginal; ´internal mods´ are not worth the cost.
Freeing up the exhaust and Cap Weir´s MAF mod are basically it.
A different program cán result well but is far from economical and also illegal here.
Whether wíse is a matter open to discussion, but lightweight/underdrive pulleys do give some gains as does deleting the airco.
Gearbox is a good and possible modification. Technically not allowed but will stay undetected.
Mine though has a C52 with LSD; with all the weight reduction and marginals adding up is not at all bad, would not want it shorter and it is nicely spaced too.
Fun with the marginal power gains it is