need some input

i have a 1991 probe it has a v-6 5spd with a 3liter. i just put a short shifter and a bolia exhuast is going on on monday. i just want to know what else i should put on it i want it to be fast i keep up with my friends 1999 honda civic si but i want to beat him so i am looking to spend around 300-400 dolers so give me some suggestions thanks.

intake. header, and test pipe...if you are keeping up with him now then that will help you beat him for the cheapest