Are there any other engine mods left?

 

turbo / supercharger. upgraded altenator / battery? those cool wire loom covers and you deff need the killer glass radiator hose.. looks sick, but not realy a perfoprmance mod.. and of couse of you go turbo, you;ll need injectors and fuel management...
and a better clutch / flywheel.. internals...

 

Ih8onyu, thanks. I don't think I can ever afford to boost. The upgraded alternator/battery sounds like a pretty cool idea. Do you know if they make upgraded cams for Scions?

 

nah, no adjustable cam gears, due to our vvti..
sounds like you have done about all you can do. now it's time for weight reduction!