Ratings are made by the maker of the tire. They are not consistent between different makers.
A 200 from one maker could be a 300 from a differnt maker.
are the RE040 (140 rated) on the MSP a nice grippy tire that is not going to last that long? yes they are but they are not as grippy as something like the MX or the RT215/RT615 (or even maybe the fuzions that you have)
Legacy GT - March Fastrack - In DS
http://www.scca.com/_Filelibrary/File/05-03-fastrack.pdf
It was not eligable to compete last year as a new model.
Also all the changes are just out for member comment and may or may not actaully happen at this point.
I am hoping for the MSP -> GS to happen
That would put me directly against the top driver in my area if he sticks with the 05 Mini next year and I ran the MSP.