What's a safe temp range to run the GS15R engine in? One of my local model shops told me 130degF(i'd been running a little higher than that before) and the performance has dropped a lot since I adjusted it, does anyone else here have the same and what temp does yours run at?

I believe the right operating temperature for the GS15R is approx 230-260 F. They do run hot, but this isn't a problem. Don't tune by temperature alone, tune by ear and eye. As in...make sure there is a visible smoke trail that gets denser under acceleration...

Have at look at http://go.to/solaspeed
Some good GS15R information here from memory.