Roller Rockers? Intakes? AHHHH!!!

[BensRanger]

OK guys so I have posted a couple of times about some new mods for my 05 fx4 ranger and have gotten a lot of mixed responses. I was looking for something that increase gas mileage and also gives me some more power. I've had a number of different things thrown at me from exhaust systems, roller rockers, air intakes ect... But I have yet to get a straight forward answer.

Intakes- Was told to get one but then found out that my ranger already has an cold air intake.
Roller Rockers- Has something to do with changing my camshaft to reduce friction(about as much as i could get from wikipedia.. yea i wikied it o.O). Useless on a truck?

So can someone walk me through what the benefits of different mods would be including the mods I said above. Tell me what it does and how it would benefit a vehicle and if it would benefit my Ford Ranger. I apologize for my lack of knowledge, but i figured this would be a good place to get educated on this topic.
Thanks everyone!
Ben