Modifications which increase the performance of the car
Also modifications which allow the car to better cope with increased engine performance
For example a swirl pot setup does nothing to increase performance but it is a valuable addition to a high performance engine
Higher performance means higher oil temperatures. The 3S-GTE already runs high oil temps so fitting an oil cooler is a very good idea if you're pushing up the power!
One of the problems with fitting a FMIC on the water to air cars is the ECUs monitoring of the chargecooler system The easy way is to leave the completely redundant chargecooler pump in place. This article shows the other way!
Once you start modifying for performance it's wise to keep a good idea on your engine's vital statistics.
Here's one way, filling the DIN radio slot with a custom gauge setup
The quest for more power often leads to new turbos. Here's a guide on what to look for when choosing a new one