Most light twins on the FAA’s registry don’t fly. Safety, Insurance, training, and the cost of fuel are the reasons for that. The ones that do fly, can be modified. We just need to roll up our shirt sleeves and do the work. Many of the ones flying have had higher compression engines STC’d with no approved OEI performance data changes in their AFM. This can be undone, and turbocharging can be removed. This has been show as an option on certain AeroStars and Navajo’s. And I’m no environmentalist. I’m an A&P with 40+ years experience and an ATP with lots of twin time. I’m just tired of the dirt that accumulates in our combustion chambers, and I know how clean the ones are on my cars.