If you want more power its simple really, more air in, more air out.
I agree with others above,
KKM True-Rev is a MUST HAVE!!! only $90 plus shipping
A nice freeflowing exhaust, if you must have Flowmasters on a v6, I would DEFINITELY get Deltaflows, you don't want your truck to sound like an angry bumblebee. Plan on spending no more than $250 total for a custom exhaust set up from a good quality muffler shop.
A chip is a good idea. I'm currently doing some research and looking into buying a Superchip myself, and I've pretty much made up my mind to get one. They're around $230 (you can get them from the same place you get the KKM True Rev so if you decide to order both at the same time you'll save some on shipping) and from what I've heard are WELL worth it.
With those 3 mods, you'll be at right around $600, and should pick up a realistic gain of at least 10hp, maybe more, but it'll sure feel like more. Your truck will be completely different from the way it was when you first bought it.
I'd consider my truck fast, fast for an 2-ton Explorer AWD certainly. I'm not it the same league as say Troll, but Troll is really in a league of his own. (lets just say this guys Explorer is somewhat reasonably decently rather slightly just a bit faster than stock

) Having a few performance parts on your truck really makes you enjoy it that much more, and it may prompt you to do other crazy things... I just ordered 5.0L badge for mine... heh heh heh........... ......ok i'm an idiot.. but thats what happens when you get 0 hours of sleep.