A tune will likely net you a few more HP/tq, as well as get your AF ratios to a desired level. Slight performance increase with a possible increase or decrease in MPG depending on were your AF lands. Our ECU is fairly adaptive, as my car has a safe AF ratio and made some good power from the bolt on mods and im still on stock tune.
If you are not messing with the intake you absolutely do not need a tune. In fact i would not waste your money unless you do.
