That's something I'd like to do, too, whether it be in the Boxster or any of my other rides. It would be fun to run on different tracks around the U.S. I'd also like to make it to more autoxes around the U.S. and Canada and run at Nationals someday. For the past few years I've mainly run with our local club here but have also gone to events in North Dakota, Minnesota, and Wisconsin.
I'm afraid I don't know the M030 spring rates right offhand. The only spring rates I know for certain are those for the coilovers I'm having built for my '06 Miata.