A tune up is always a good start! Spark plugs, wires, fuel filter, oil change, air filter -> K&N 4 sure! Low vesco oil too. That's important alot of people out there like to run 20-50 because they beat up their cars but it is actually robbing power. Saw that on Speed TV. Another thing I saw on speed vision was change your fluids to Royal Purple and it should give you 8hp dyno tested. Diff fluid and trans fluid. I put long tube headers on my car but it was when I was doing a motor swap. Real big pain in the Arse. BTW headers improve gas milage.... If you can keep your foot out of it. Oh a MassAirFlow sensor Around 300 bucks 5 minute install. You won't notice much power unless your car is highly modified though. So I would say... Do nothing and drive that baby like Toyota intended slow and gutless.