After surgery my boost can only get to 23 if I really try hard. Still seems to have the same power and my mpg has remained the same. IIRC Cheezit mentioned in a thread he had lower boost with the same power also, and it was just the nature of the beast after the delete. I think he was around 22. Your 20 seems a little low and may very well be from some slight leakage. Are your CAC boots oil soaked? If so, you probably have some small leakage on the intake side and may want to replace them. Did the exhaust pipes go together flush after the surgery?