11/1 is pretty high, while stock 6.1 engines can run about 9 psi safely, it is more limited on them as the 6.1 tends to exhibit stretching of the head bolts at that level and bleeds combustion gas into the water jacket. Initial signs are elevated cooling temps and puking coolant out of the overflow tank.
With 11/1, I would venture to say no more than 7 psi, and you would certainly want to be agressive with water/meth spray which might allow a bit more.
The bigger issue for a 2011 is the fact that tuning is not available, and due to the changes in its vehicle architecture, it may be some time before anything is available. The 2011 is a hybrid system using some of the old CANbus from 2010 and earlier, and the new FlexRay system from the 2011 300 and Charger systems.
While the 2011 Challenger "might" still use the NGC4 controller for the engine, there have been significant changes in regards to the combination and/or replacement of other controller modules and the communications protcols and even the OBDII port wiring is different.
If you have a 2011, I would not contemplate any major modifications until it is known when and what kind of tuning will be available.