A supercharger is the only way to get that much but I think the Explorer Express kit has been discontinued. Headers, Y-pipe, hi-flow cat, exhaust, intake, tuner, and underdrive pulleys is about the max and would probably net 30 hp at most.
I have never heard of the express kit, I am wanting to get more power from my v6, I got a friend with a later model with a v8 but it didnt feel like any more power than my v6, I seen some computer chip hook up on Ebay but don't know enough about them to know if they are junk or not, dknt want to spend more that a few hundred
You're not going to get even close to 50 hp for a few hundred dollars. The chips are junk. The best you'll be able to do is what JohnnyO posted. For a few hundred dollars, choose one of those and hope you can get close to 10 hp. Each of those is going to be a few hundred by themselves. Most seem to give best reviews for the SCT tuner as far as bang for your buck.
+1 on eBay chips being junk. All they really do is fool the computer into running in choke mode and getting a little richer fuel mixture, which doesn't really help much. You get what you pay for and the SCT tuner is about $350 last I looked. A cat-back exhaust costs about the same. Those two mods are the best bang for the buck.
Overly technical section:
The way you make more horsepower is by making the engine more efficient and breathe better. On a normally aspirated engine there is only so much you can do on intake and exhaust before you are limited by the camshaft(s), which is what controls airflow through the engine. As far as I know there are no aftermarket performance cams for the 4.0 SOHC. There is no chip or tuner that will magically unlock a hidden 50 hp.
You can get a cam, check out the link below. However, that will require their heads too....
I have one of the Explorer Express kits and it adds some pep. (It was installed on the truck when I bought it.) It will push five pounds of boost, but I've never put it on a dyno.
There are 10 sec V6 mustangs, so power can be made. You've just got to pay to play!:bwahaha:
Ok iI guess 50hp is too much. Which is the best way to get aleast 10 or 1hp or some torq boost. My ST is real weak on the take off but once on the highway its fine.
Why not focus on removing weight instead of adding horse power. Gut the interior, remove the air conditioner, radio, etc. cut out the bed, remove the spare tire and brackets, cut out the fender liners. Remove as much weight as you can and it will go faster and get better gas mileage.