Swings a larger prop. More Power. Betterfuel economy. Different fuel. Different smell. Quieter operation. Fewer field Accessaries needed.

I contemplated doing it myself, but never got aroung to it. Although a fellow club member converted all of his engines and really liked it. Don't expect a lot of speed. Flying a Cub I quess you don't need that.
Diesels are very popular in England.
The only tough thing is learning to adjust the head for the proper combustion pressure.

GO FOR IT !!!! [&:]