Cheap Horsepower?

One of the car mags did an extensive test of things you can do to a car to add power starting with the least expensive and working up to the most expensive and they did dyno tests after each addition. Bottom line was there is nothing you can do that will make any difference that costs less then around $300. The air filters and all that other simple crap is all worthless. The least expensive but actually effective thing you can do is to change to a less restrictive exhaust system and you will gain around 15 to 30 hp depending on how bad the original one was and how much noise you are willing to listen to. They even tried adding bigger throttle bodies but without the better exhaust they got almost no increase so taking the screen out of the factory TB is not likely to do much. The key is BREATHING but it has to be a meaningful improvement. After the better exhaust then next thing the did that made enough difference to worry about was changing the heads, which is hardly cheap.