I ran the Stage 2 map for a short while (~2 weeks) until I could get in for a protune with Sunny (Airboy here in Calgary). I ran Husky94 exclusively and didn't notice any issues, no hesitations or wastegate flutter (although I was on a VF34 turbo not the stock TD04). The Cobb OTS maps are pretty rich.
Do you have an air-fuel gauge? You could also log A/F on your AP and see if it's pulling any degrees of timing. Also, your SG9 will be similar to an 04-07 STi, so there might be more info on NASIOC regarding Cobb Stg2 maps in mountain regions. If you're on the stock turbo, I would expect fewer issues with leaning out, as the stock FXT injectors flow enough fuel to support the larger VF STi turbos.
