Sounds to me like either your idle is a little too low, or your LSN is a little too rich, so I think you are definately going in the right direction. Sounds like you are making some good progress. My XT2 should be here early this week I hope. I just traded another r/c for it, and I already have a new set of tires and wheels to go on it as soon as it gets here
They are supposed to be good buggies though and the XTM 24.7 is supposed to be a great engine too.
Oh, and as for the temperature gun, that can be a good tool to have at times, but dont use it to tune your engine. Tune for performance, and smoke. If you have a good idle, snappy acceleration, and a light smoke trail, then your engine should be tuned near perfect and a temp gun isnt really needed. Of course it never hurts to see what you are running at just to be sure though. I dont have a temp gun and havent killed a motor yet, so all i am saying is dont tune solely with the temp gun.
I think you are really going to like the 1/8 buggies though. In loose dirt/jumps they are an absolute blast to drive, and they are extremely tough too[8D]
Keep us updated with your progress.
Eric