Picked up my car from the dealer and they said the boost dropoff is normal. They told me for the boost to hold while I have it floored, I needed to have a supercharger but the Solstice comes with a turbocharger.

On my own, I have noticed a longer hold on the boost since switching to premium from regular. The dealer told me I could run regular when I bought the car so I tried a couple of tanks but was not satisfied. So now I am switching over to Shell 93 Octane.