hey fella sorry its took so long to get back to you ! i would run a 8.5 at around 9 which would be a 23 pinion on an ansmann
regarding lipos i have just got some from the component shop vp 4500 at around £47.00 and brc legal but its up to you dont think you can go wrong as long as they are brca legal

Now then what pinion should I be running with a 8.5 motor. I have the radio gear and servo, just need Charger, Speedo and Batteries think I'll get the batteries from Demon products TP2S5400V6 7.4 5400mAh.

Ian