Thanks for all responses. Just a little update. I have been using premium gas from mostly cheap gas stations for a year or so. Recently I decided to switch to the more expensive top tier gas stations and i'm noticing better performance and MPG. With the cheap gas I used to hear some slight engine rattles once a while but it now runs pretty smooth since switching. Won't be using cheap gas anymore unless its the only one available. Also I have removed the Pedal Commander. I think throttle response is better with it as advertised but I feel like its confusing the engine ECM. A bit too jumpy. Also think that the "Competitive Mode" feature works better without it.

 

After a little injector cleaner in the fuel, I have had similar positive results buying only to "Top Tier" fuel. GM recommends it.

 

Yes it makes perfect sense. Will mostly be using top tier.