GGR previously mapped M600 and it still goes,hasent melted down and runs pretty well.
May be they restrict things a little more than others but in my opinion thats a good thing rather it be a little slower than blow up!

Why do people alwas slag other people you never know what you get until you try them out. A friend of mine recently had his car mapped ( not going to mention any names) by a well respected company and was not impressed at what he got.

P.S Mr manchester it was me