[S|Lv3rBu||et]

Three things that will make the most difference in your off the line acceleration are:

1. Cold Air Intake: many brands are made, use the search function of this site to see which one is best for you.
2. HotShot Header: widely known to be the best mod for the celica GT. It'll give you some nice low end torque, and otherwise improve power all over the RPM band.
3. Lightweight Flywheel: many are made some are lighter than others, you don't want to go too light for street use. The install on this one is fairly costly but it's worth it.

Some other small mods you might want to concider are:
Polyurethane motor mount inserts by Energy Suspension: improve torque delivery and improves throttle responce.
Brass Shifter Linkage Bushings by SpeedSource: greatly improve shifter feel, making shifts feel much more direct and precise.

Good luck and have fun with your car! If you really want to get a blast out of it... take it to an autocross meet!

 

[S|Lv3rBu||et]

Originally posted by slidr
You won't really feel anything with any of these mods. It's hard if not impossible to feel a 5-10 horsepower increase. It's mostly in peoples' heads.

Be that as it may, I can assure you that the experience driving my car (disregaurding handeling) is entirely different from that of a stock celica.

....and you know I would bet money it's faster