With regards to Lo Presti and commercialization- What people are missing here is the aircraft market has changed, drastically from the time when Lo Presti developed the cowl STC. Not too many years ago, aircraft values were very high. Cowl STC was more geared towards people with M20Es and Fs than it was people with Js. Prices were such that you could buy an M20E, put the Lo Presti cowl on and have a faster plane for about the same, or cheaper than an M20J.
Then the airplane market tanked. It seems to go ever lower. People are now parting out planes when they need an engine overhaul instead of rebuilding. With prices the way they are, selling speed mods is indeed very tough.
Oh yeah, the "Just sell them at $10,000 installed and they'll make lots of money" theory is about on par with the "Cessna should just sell the Skyhawk for $100,000 and they'll make billions" argument. Neither are based anywhere near reality. The costs associated with developing, certifying, producing and insuring aircraft and parts is astronomical and the available market of potential buyers is quite low.