I totally agree about questionable parts and muddying the conversation. Not long ago, I learned about a Highlander that someone attempted to put a Corvair engine in that didn't turn out well. Checking into it more, it turns out the guy who did the installation did it his way with an engine of questionable condition, using questionable parts, and he did NOT follow William Wynne's instructions/guidelines/recommendations/etc. Of course, all most people hear about is that it was a Corvair engine that didn't work out.

I recently watched a Corvair powered Panther plane perform aerobatics for about 45 minutes straight. Engine sounded really good and it was great fun to watch.