Modifying glow engines seem to be very effective on RC car engines. They give extra RPM but I notice that on track its on the high end only and not low end power. Standard planes with engines that run in the 13K-15K range do not seem to get much benefit from all that mods. Its better to get a tuned pipe or a better/bigger engine. They did come out with a super charge system for RC cars of .21 size and I think maybe .12 also. Its expensive. I think a YS is cheaper and more effective.

What do RC cars do (my terminology is far from accurate):

polishing the crank shaft
opening the ports
smoothening the ports, removing the 90 degree edge on the port
adding a turbo scoop on the crank
opening the crank shaft
adding a dollop of epoxy in the crank opening to smoothen the fuel flow
cutting some dracula teeth like shapes beside the ports

An idea can be found here:

http://murnanmodified.com/#more

One thing ... don't argue with Dar about engines ... he know TOO MUCH! Hahahahaha ... how you been Dar?