my friend has a 99 mustang V6 with a 3.8 in it. he has a cold air intake and gears in it. wat else could he do to it to get more horsepower in it?

 

Get duals next, that's true duals (v6 x pipe with GT cat backs), then if you really want some power, do my mod, minus the swap thing, I have a single port and I am upgrading to a split port, that's the mod in my lower sig.