I sold my smartech buggies, but I kept the 2 of the smartech engines that I had. Even though they are cheap chinese engines, I found them to idle forever and hold an awesome tune! I use one of them in my nitro evader as a winter beater engine. The other engine is still a spare engine I have laying around.

The engine in this vid is the smartech one:

http://www.youtube.com/watch?v=cV9fGAZzcB4

Also, you said your engine stalls when you hit the brakes. Pull the air filter off the engine and look into the barrel (when the engine isn't running, and the servos and controller are turned on) and hit the brakes on the controller. Watch to make sure that the barrel isn't closing more when you hit the brakes, if it is, you need to open up your idle screw some more. It might fix your stalling problem.

Here's a pic of all my current RC toys. A long way from my smartech days....