The Redarc Tow Pro adds Automatic mode over the previous model (Inertia sensing) for highway conditions, trailer brakes are applied at a proportional level to the vehicle braking level. I have also had the P3 in my old Prado 120 and was happy with its performance the Redarc just suits me better...
Computer is reporting an average of 8.4L/100 around town but based on Fuelly its 9.1L/100?
I recently towed my 2000kg caravan from Sydney to Cooma and back again and did 12.9L/100 according to the computer.