i got some farily new magnecors u can have for 35$ plus shipping...
purchase urself an apexi neo and lean out a bit.... also reccomended to get a WB A/FR guage, but i can pm u my tables that seem to work pretty dang good.
You can not commit crimes in a Aveo. Its just not fast enough.
its a piggyback programmer.. kind of like a tunable chip option still require you to use the parameters of you stock parts, but allows for adjustment for either power or economy..
I would say you could buy a head off ebay (like $200 ive seen) and then port it out and deck it. Bigger valves. That *might* add 10-15 hp or more. You would have to go to premium fuel. And might need something like the NEO to adjust for it, but you might not (can't say since no one i know of has done it). You could also look into a custom ground cam.
there are things you could do to make your car quicker too, not adding HP, but more HP responsive. Lighter wheel and tire combinations with better traction. Less weight in the car overall. Adding sway bars and supports to keep the car level, to put more power down. Changing the final drive gear (not sure if possible. but in most makes is interchangable, switching to the auto gear raises the ratio)
Other than that there are little tricks. I've seen someone who match ported their throttle body. or you could find a __mm butterfly, and port the whole thing, and put in the correct bigger size butterfly. you can also do the intake manifold (although plastic be careful).