I installed the 2011 Attitude Adjustment plate on my '02 X30 and absolutely LOVE it. However, as jafo9 states, it really is only to help decrease porpoising at speeds over 20 mph, in my case. I use it in the all the way up position when boarding or surfing. It will cost you about $1,600 if you install the factory position guage.
2002, X30, L-18, Red Metal Flake (the possessed boat)