l already have a big exhaust, the cheapest options would be much appreciated..

Put the letters WRX on it :)

l am not sure you're going to find much power cheaply, go to NOPI.com and check their E-CAT, they have what you need, next step = TURBO

The cheapest way to gain power in most cars is nitrous (for around $600 on a basic setup u can gain over 40hp instantly to the wheels. If do not want to spend more money dont get greedy with nitrous. Your computer/fuel system can handle an amount of nitrous without further upgrade. If u go beyond that u might need a computer to deal with the fuel/air mixture & larger injectors/fuel pump to deal with the extra fuel the nitorus will need.

Other cheap upgrades: Underdrive pulley, computer chip reprogramming (to obtain more power or raise the rev limiter), cold air intake.

For turbo cars like yours u might also research changing the blower internals to get more compression

A computer chip will do it if you do not mind buying high octane fuel. Another idea would be a K&N air intake kit, worked for me.

Next is the intake, then underdrive pulleys, get your computer re-mapped, boost the spark, and then get some headwork done. Make sure you do a volume for forced induction if you plan doing that later and velocity if you are going to stay N/A.

Headers are not that expensive and can give you a nice moderate increase in horse power. Also Cobb Tuning makes a great cold air intake system. You definately feel those upgrades. Another smaller upgrade is to change out the existing plug wires and spark plugs.

For all your subaru upgrade needs, check out cobbtuning.com. Very

Good luck.

All late model subaru is have whats known as an intake resonator. To find it on your car, look for where the intake tubing runs into the passenger side fender. Removing the resonator performs just as well as $250+ cold air intake systems. The best part is its free, and just takes a few minutes. For detailed instructions search the forums at NASIOC.com for intake resonator removal.