It would be worthwhile to change out the intake (or at least the filter) to increase air flow - the trick is to increase flow at both the front end (intake) and the back (exhaust). Your VX ECM hasn't yet adjusted to the change so resetting is always a good idea whenever you make performance changes.

I personally did not see an increase in miliage with the PV, but others on the board have reported it to be so (driving habits, as Morgan has said above).

-- John