Hector, check the one Osvaldo has with a Rabbit. That's the sweet spot for a everyday flier. Mine used to have a Super Eagle, way fast, but too heavy due to balancing requirements.
The Cheetah may be a better choice than the Rabitt, as you get the extra thrust fro limited weigh increase.

From Milton experience with the K-80, seems like a reliable engine, but the spool-up time will kill you in case of trouble. Not sure if his engine one a unique case, but I will stay away from it.