5 liter = 352? Probably meant 302 but anyways, for a good full exhaust you are probably looking at about 1000 dollars so for a budget minded person there are better ways to get more power. Your stock exhaust is probably good up to high 200hp mark anyways. You can get your stock intake ported or go for a GT40/Explorer/Cobra(all pretty much the same) intake. The explorer ones can be had for pretty cheap. Gears would be a good upgrade especially if you have an automatic. Go 3.73 for an auto or 3.55 for a manual. If you go any steaper you will really start to see your gas mileage change. Get a K&N filter for the stock air box. Don't bother getting a cold air intake because the stock one is pretty much one anyways. Stay away from underdrive pullies. Unless you upgrade the alt you can very easily run into charging issues and potential overheating issues. Definately not worth the 1-2 HP for all the other parts you need to replace in addition. Maybe a larger throttle body and mas air meter. Those things should keep you busy for a while. Another cheap trick is to bump your timing from 10* to 14*.
Kevin