The re-engining gives the aircraft the POWER to support higher MTOGW without compromising runway limitations. The MTOGW of the aircraft, however, is a structural matter. Increasing gross weight limits requires strengthening the airframe and "heavyweight" landing gear.
Conversion of the aircraft to a freighter at 190K gross weight can still be made stage III with installation of hushkits. The $8-10M price for the Super27 without modifying the airframe to increase the gross weight to 220+ seems contrary to reason. The prototype Valsan was test flown at 235K back in 1988.
The only benefits that remain are the fuel economy and performance. I guess a pocket rocket with a big door is enough, regardless of what it can carry.