Twice the fuel flow... but also more speed! For what it's worth, I get better miles per gallon in my V35 at 170 kts than I got in my Piper Archer at 120kts.
Archer = 120kts/10gph = 12 MPG
Bonanza LOP = 170kts/13GPH = 13 MPG
If you don't have GAMIJectors to run Lean of Peak, get some and learn how to use them
Sure, I could probably get 176 kts on 16 GPH running rich of peak, but I would be burning 3 GPH more to get another 6 KTS. Not worth it. I know the Grummans are more efficient than the Pipers, but the Bonanza MPG is not shabby considering the speed.