15.3-15.0 seems to be pretty common for the stock SS. A couple of guys have reported some high 14's but I am not sure how much I belive it. Personally, I did a 15.3 with only 950 miles on the truck. Now-a-days it is a bit quicker at 13.9, but it is not stock anymore
I am not sure how much the AWD helps at the track. The surface at the track tends to be sticky enough that 2wd can keep hooked up (at least until you start with the heavy mods). On the street though, the AWD is handy. Unless I hit a slippery spot, it keeps a good grip, and leaves the Hemis in the dust.