when my 2011 535xi has warrantly work done due to it's suspension, factory programming was redone at the dealer via Germany. it did eliminate the lag issue on my 2011 so i due think there is some ambiguity on what some (dealer service depts) see on test rides vs. what we feel in the seat of the pants.
after the reload of new software (care was in due ot steering problems) hesitation issue went away.
12 550xi Dark Graphite Metallic II. Convenience, Cold, Driver's Assistance, Premium Sound, Sport, BMW Apps