I can't speak for the year difference, but if this is for SCCA street/stock class, make sure you get the M030 sport suspension option. Also, refreshing the shocks with good quality, new ones and also use fresh bump stops as they are an essential and active component of the suspension, which work in parallel with the spring.
Someone was selling a set of JRZ double adjustables... those would be sweet for SCCA stock with the M030 springs. The coilover springs wouldn't be stock/street class legal, and probably also couldn't use the aftermarket upper mounts, but those are some high-end shocks:
http://986forum.com/forums/boxster-parts-sale-wanted/64588-jrz-doubles-fs.html
What are these recent rule changes you speak of - Got a link?

Good luck, and have fun!