There are wagon specific coilovers. The Tein Flex wagon specifics seem to do really well. Joeyy on here used to regularly kick my ass in ESP in a similarly modded wagon and now K-Dogg (Kevin) runs them and loves them too. But I like the comfort and dependability of springs and struts.
These are the springs I run:
http://www.crucialracing.com/products/springs.php. I wonder how they compare to the RCE ones.
We're (Alex and Nick Clarke) planning on installing the Konis next weekend (not this weekend). You should join us.