Tom,
In all fairness I find both JAG and Wackerengines to have equally good parts. But I do have preferences.

Wacker engines make a great muffler- If you pre-measure they will cut them to a specific tube length etc. (see pic) If you don't pre-measure they will make them a standard length and make the muffler tubes threaded for easy cutting. That is what I did but I had to use JB Weld to seal the threads.

I also did not use the JAG engine mount because I liked the idea of building an engine box and mounting the engine with a flat plate. (Also in pics) This saved space and made running throttle cables and fuel lines a bit easier. It also reduced the amount of vibration transmitted to the plane by reducing the leverage (overall length) of the engine.

When it was all said and done I used the JAG prop mounting shaft and Wackerengines muffler and mount-plate. In the future I will purchase my parts from wacker. (for simplicity). Total price for conversion parts 52.00

Performance:
So far the engine has been a great performer with one exception. On my first experimental flight with the Sukhoi my engine was severely out of tune and my plane was also extremely tail heavy. (But the engine did not quit) It continued to run and keep me in the air until I could decide on how best to land the plane.

Prop: 18x6-10
RPM: 7100

Lessons Learned:
When tuning the engine let it run for at least five minutes at low medium and high throttle settings to check for proper engine performance. Also balance the plane better.