I ran mine for the first time at Kidderminster national this weekend and was VERY impressed
The gear ratios I ran were
2wd 8.5 motor = 8.4 / 1
2wd 7.5 motor = 9.2 / 1
Note this was on a very tight technical layout, I would run the same gearing say indoors but be +1 tooth on what I would call an average outdoor track.
4wd 7.5 motor = 8.5 / 1
4wd 6.5 motor = 9.3 / 1 (anticipated but not actually ran)
The Sunday track was more open so I think this could be already my average outdoor track gearing.
I hope to run again this weekend so will update anything I find out after then.
Dan