Have not compared my 330, but the flat out 30-40 MPH run at 13 Grams/Sec sounds low??
I am thinking you may have one of the crappy imitation MAF's that use thermistors???? These crappy MAF's under report airflow, usually at idle they are close, but cruising they read too low and and will cause the fuel trims to always be high.
Long term fuel trims are too high, they should be less than 3%.
Get your O2 sensors logged from cold start for the first 3-4 minutes until the engine goes into closed loop. This will allow us to see if the O2 sensors look good.