I will be using the speedster as a tug plane. So I did put a mvvs 58 on it, with a mezlik 21/12 three blade prop, and a KS86-4 4-chamber exhaust pipe in the fuse. Plenty of power.
[link=http://www.moonrakers.be/bodys/Album/vluchtboek/Biggs/speedster.wmv]Here[/link] a small video taken last weekend, it was its maidenflight.
And [link=http://www.moonrakers.be/bodys/Album/Bouwprojecten/Rearwin_Speedster/Bouw_Speedster.html]here[/link] some more pics of the speedster.

With this setup the plane weights just over 10kg (22lbs). This seems to be a lot more than mentioned by Kangke. So 5 lbs overweight compared to what Kangke says: 14-17lbs. They testflew their speedster with a zdz40 on it. That is not that much a difference. I did not add any lead, and the plane balance just fine...

@cstevec & @John_RedSox: What is the weight of yours?