Price range? Free.

Just get underneath the car and saw off the exhaust after the headers.

Yes, it'll sound as bad as it looks. If you've ever watched a Starlet autocross, that horrible, ear-splitting buzz-saw noise is the sound of a "scub" or scavenger exhaust at work. It's almost impossible to drive such a car on a daily basis.

Save yourself the trouble. Just buy a nice looking muffler (around 8-12k pesos) and be done with it. The measly extra few ponies you can get from a scavenger exhaust isn't worth the pain.

There are only two power mods worth getting for street use. Forced induction (turbo, nitrous, supercharging) or engine management (which often comes bundled with the turbo). Everything else compromises either the driveability of your car or compromises the size of your bank account.