You won't get much more performance out of it. They simply aren't geared for speed.
The most I would do is intake/exhaust good spark plugs, maybe a Ignition Box like MSD.
If you have to have more power this is your best bet.
http://www.toyotacatalog.net/M1WebGe...8-1D4CCE820050
It won't ever be a sports car. So don't think it will be after doing something like that. But it will have a bit more pep.
Good luck!
www.lcengineering.com