Wow.
The only meeting I ever had with the "feds" when flying round motors (still flying them, incidentally) in single or multi equipment was a group of inspectors passing through, who wanted a tour. I gave them one, and they were quite happy. I don't know what it is that you did that caused so much scrutiny by the FAA, but it certainly isn't the fault of an older airplane or a round motor.
Radial engines do not create a black mark on your record. A DUI does.
Perhaps the difference is that while I've spend a fair amount of time in 60 and 70 year old airplanes, none of them were "turds." Sounds like you made some bad choices.