On the 07 stage 1 makes a difference, but stage 2 is where you want to be. I wouldn't waste the money personally on a dyno tune for stage 1. I'd wait and have a protune map made for stage 2.
There are many threads on here detailing out the difference between an open source tune and an AP map flash.
I have a Cobb AP with a custom map made by a dyno tuner. The AP was used to load the map.
Professional tuning custom tailors a map to your car. While the OTS maps that ship on the AP are decent you will pick up all kinds of gains with a custom made map. I picked up +38 whp and +66 ft-lbs tq over the stage 2 base map with a custom tune. The AP is just the vehicle used to flash it and gives you the flexibility to flash it yourself or unflash it once the map is made.