Meth is not the answer on this one. Meth should be used to lower charge temps. I would never sugest
meth for fueling, that's a dangerous way to go. I wonder if the pinging that you have in that rpm band that you listed is due to the piston slap table that is in the ECM. Once that's "taken out" our cars will run lean in this rpm until fuel is added back in. If left in the car runs really rich there and causes that dip that a lot of us see on the dyno.
Either way sounds like hahn has it covered
Jay