dirtyd is right, to get vtec on a non-vtec motor you need to swap in the head from a vtec motor (such as d16z6) and an ecu that can handle vtec operation. (I dont know if you can put a d16 vtec head on a d15 block, but pretty sure it will go onto a d16 block)
For the love of god, dont any of you buy spoilers because of it's "performance potential." LIke dirtyd said, it's a FWD car and you don't need downforce on the BACK. Think about it.
If your transmission and all of your shifter bushings are in good condition, a short shifter will only help a little. Despite what fourdoor92 said, there are no drawbacks to shifting faster.
One final note: even if you get a new head for the motor, vtec won't kick in until around 5k rpm. So before you even consider it, make sure your engine is healthy enough to rev to about 7k.