Unless the factory purposely keeps the cams from reaching high lift for a reason, I doubt the avcs has anything to do with the top end pull. The avcs set up on our cars is a bottom end thing...I'm pretty sure by the middle of the power band (or round abouts) they are finished their advancing, and reached 0* advance which is high lift mode. I've just always understood the intake cam only avcs set ups are for low end. If I'm wrong, I will be the first to do some cam tuning! I still think the limits some of us are seeing is due to the turbo. I'm very close to going to a dom 4 or one of the atp stock location 30r's.
Almost forgot, I run an s203 ecu on my car...I'm gonna check out the cam tables from the stock rom and see how the factory has the cam advance.