Hi Craigb!
Thanks for the Prafa answer - I'm from Switzerland, so german is fine - I have a brand new Chassis as you have and a Tornado of Prafa too - but what I find even cooler is, that you switched for FS too! They really work great, I mounted a "tuned" FS48S on my Carson Buggy:
It turns now about 15'000rpm an goes like hell with a 21T clutch - as next I'll produce a smaller main gear (40T istead of 52T), power I got enough! The Carb is bigger of course and the channels have been "revised"

- the limitnow are the valve-springs... should find harder ones, the original can't go over these 15'000rpm...
And it really runs fine!
Cool idea
regards
Phil
PS: so these cars have been built by prafa itself?!?