Can't go wrong with custom tune from MPT. Mike there def knows what he is doing.
And TLB4, sorry to tell ya boss but you are incorrect as far as there not being different types of tunes for n/a engines. Will they be as BIG as a difference as on a diesel or forced induction vehicle? No but still a noticable difference depending on what type of tunes you get.
For the 5.4, on average, you would be looking at about 22 rwhp for a stock 5.4 and 20 torque but those gains are on a SCT tune, a custom tune from MPT prob would be able to pull lil more power out, but you would want to contact them to see by how much, they are a vendor here on the boards as well and I'm sure could help you out.