Ok first A K&N on a 5.0 engine will add an honest 5 horsepower minumum. This is if you also remove the air silencer in the fenderwell. Number two to the guy saying reflash your computer. The 1994 Mustang
GT's computer cannot be flashed. You must add a chip. Here is the best and easiest way to add power.
Cold air kit, pulleys, cat back exhaust, chip, gears 373, throttle body 65mm, headers. The chip will help by giving a more aggressive timing and fuel curve and also take away the lost performance that 1994-1995 Mustangs had when shifting. On the 94-95 the computer cuts timing at shifts to help prevent transmission breakage. The means that when you shift at full throttle the car isnt giving you 100% power. A chip will also make an automatic shift firmer. You shouldnt be asking a bunch of people on yahoo about how to make you Mustang faster. Goto a good Mustang forums website and ask the die hard mustang guys. And by the way you are in luck. Most performance parts for 5.0 engines from 88-95 will interchange with each other and as any gear head knows the Mustang has one of if not the strongest after market of any single car. $700+ million last year. If I were you and had $500 Id get A coldair intake, pulleys and a catback exhaust. They were my first mods and you can feel the difference. Now if you want to perform with the newer mustangs you are gonna need alot of work. Cylinder heads, cam , intake etc. Dont listen to people who have never oned a 5.0 as they dont know what they are talking about. They will tell you a chip will add 50 horsepower and that an electric supercharger will work. An american muscle is a decent vendor but they are not the best when it comes to 5.0's. Your best bet as I said is goto a good Mustang Forums website and ask the diehard 5.0 guys and they will help you out alot.