12 year old bump?

For the 6MT, short rear gears are the best NA mod. Not really a power mod, per se. It rearranges the power you have in a way that's awesome but still driveable.

For handling on the G, any brand aftermarket sway bars.

If you do nothing else to the car, do those two things.

 

Long tube intakes, catback exhaust, HFCs tune. If you want to add a little more upper and lower ported manifolds, headers.