Actually you will see around a 15 hp difference with an intake. I put a Performer RPM intake on my stock head/cam car and I went from a best of 95.89 mph to 98.51 mph in the 1/4 mile....pretty decent if you ask me.
I recommend the same things as the other guys: gears, shifter, etc... I also recommend getting underdrive pulleys (about 10 hp), full exhaust or just a catback (it's a lot more fun driving a car that sounds good). And if you're really serious and have lot's of money, then look into getting different cylinder heads, and an aftermarket camshaft....you'll see huge gains in power with those.