I know some of you are debating getting this and are reading the thread to help make a decision. (As I was) Maybe my two cents can help.
I'm getting the stage kit for many reasons. None are the tune itself. I wouldn't get it if it didn't benefit the car in some way. But there are some very good reasons for me to get it. The most important to me is making these kits profitable for Buick so they keep coming. While this alone wouldn't do it for me, I think it's important so we might get a Stage II or Stage III from them in the future. Having a stage setup might also make the car worth more in the future. Sort of like the old GS Stage add-ons. They need a badge or sticker so people know it's a Stage setup.
The stock airflow tubing sucks. One of the first things I commented on was the horrible plastic duct work. I never purchased the ZZP upgrade because it pulled hot air from the engine bay. I didn't want to fix one problem and add another. So I put a K&N drop-in filter which still uses the crapy stock tubes. That was the cheapest way out. The new Stage system solves that problem for me. It not only looks good but pulls colder air. It also seems smoother which will help keep turbulence inside the tubes to a minimum. The less resistance the air meets on the way to the turbo the faster you should spool up. May not be much but something is better than nothing. It's all wins for me.
I'm happy with my IPF Tune so I'll see how it works with it.