Surefly was very polite and nice to deal with, just not successful. 2nd mag also arrived reasonably promptly but was not set up correctly and ran rough. It was easy enough to fix, just reset dip switches. I cannot figure how they don't set these at the factory, especially after it was a customer...
Installed Surfly with a certified repair station on a new (0-time) Lycoming. Engine ran fine on the test stand with mags. Engine stumbled with Surfire on, smooth on the mag. When Tech support finished "helping" the engine will no longer run at all. Their "advise" made no reasonable trouble...