Guessed right about the powerloss. IMO the clearances don't change around the OD-section between a 500 and a 518 so there's no gain there.
My car's mileage is pathetic and absolutely no better than running around with a 904 transmission.
It has become much more fun to drive with the OD, but hardly any improved fuel-efficiency at all.
My hopes are settled on the better first gear of the A500, a matching 'newer' design stall convertor, lockup, and a lighter rotating (and rebuild) internal assembly.
