Do you have a boost gauge? What boost were you seeing when you brake boosted and what is your maximum boost now? How are your AFR's when under low throttle boost situations? I would ask about IAT's but I don't imagine you have relocated the temp sensor from the MAF.
Gonna get both for readings at some point but don't have them. For now I'm taking it easy apart from the 0-60 runs. My guess is I am running 8-9.5 psi and the IATs by definition are higher. But that is conjecture.