How can i get more horsepower out of my 96 mustang v6?

Well with the only option not being an option You can stroke it to a 5.0 V6, Put in a custom ground Comp Cam, find the heads/intake from a 99+ Model, forget about over the counter chips as you will have the computer custom tuned now, better yet scrap the stock and replace it with a megasquirt controller. Forget the supercharger and put on a dual turbo setup. Of course this will net you a car that will finally keep up with mildly modified V8's and will have cost you about 4 times as much as buying a V8 car to begin with. Also you could find a wrecked GT and do a full on drivetrain swap, this is VERY intricate swap requiring a lot of who woulda thunk it, parts needing to be swapped and requires a BIG Bottle of Excedrin Migraine. Hope that helps.

sell it and buy a GT. The performance to dollar ratio of this upgrade is more than youll get with putting mods on the 6. if thats not an option due to costs, then maybe you shouldnt be modifying your car to begin with.

you can get the fuel system upgraded, the ecu reflashed , cam, and maybe a turbo

Put a turbo on it. Get rid of it and buy a V8 version.

umm stick a match in the gas tank and watch it blow up then collect insurance (this isn't legal) and get GT!

Try removing heavy parts like back seats or heavy metal. This will give you a little more speed.

the stock T-bird supercharger for the 3.8 are easy to find on Ebay