The best "tuner" you can get hands down is an HPTuner MPVI2 and then have it custom tuned by someone who knows what they are doing. However, none of these are going to help you get better fuel economy. That's a myth that some will perpetuate, when in reality anyone who is claiming more MPG is just dealign with the placebo effect.
Someone will come on here and argue with me about this, to which I simply won't respond, because no matter how much they want to convince themselves they saw a MPG gain, they are wrong, plain and simple.
Anyways, you can get a bit more power with a tune and some drivability. Superchips is okay I hear, but HPTuners would be the professional way to go.