For me personally, if my car is going to sit longer than 1-2 weeks I will put a few drops of after run oil in the motor and down the carburetor spin the motor a few times and set the piston all the way to the bottom. At the end of every run I clean the air cleaner and set the piston all the way to the bottom.
Continuously running the motor flat out can cause over heating. You really shouldn't run the motor over 270 degrees Fahrenheit. Try richening the high speed up about an eight to a quarter turn.
The .18 conversion won't wheelie but will give you better speed going through grass and such.
I don't think that they are going to stop the Fun Factor anytime soon but I could be wrong. They sure don't promote it very much and their rep isn't very helpfull. My LHS is about to quit doing business with them because of this ( can't type what the owner of the LHS said about the rep but trust me it wasn't nice).