Pulley will help for sure, but will need tuning. More airflow means MAF transfer will need to be tuned, as well as Power enrichment tables.
Tuning is not about boost, its about airflow and the calibration of the MAF to determine that airflow. Flow and Density are different things. You are down on boost and HP relative to sealevel due to less dense air, and less oxygen content in it. Spinning the blower faster increases airflow consumption before the rotors and across the MAF, and increased charge density post rotors into the heads. The ECU determines fueling based on that airflow. a Certain MAF frequency is an expected to be a certain airmass, and a commanded injector pulse to fuel towards that airmass appropriately. Now the hellcat looks to use both MAF and MAP, and I haven't seen the stock calibration myself yet, so I'm not exactly sure what strategies the ECU uses, but generally anything that changes airflow into and out of the motor substantially ( and a 20% overdrive is substantial) needs to be calibrated correctly.So even if we're losing approx 2 lbs boost still needing tune if just trying to get boost back up to stock levels? Which if can be done I'm OK with but what a pita.