I would much rather create something than just buy it. Thats whats so much fun about conversions engines.
When you do your thrust tests, do them with both the 18-8 and 18-6 props. The 18-6 will help with landing but there may be a sacrifice on the top end thrust. Also, these wacker engines run the risk of destroying them selves, once you get them over 8000 RPMs. The con. rods are the weakest link.