What kind of track? ArnO has posted some of my set-ups on Petit RC:
http://www.petitrc.com/setup/atomicc...CarbonCR2.html
Pick a set-up from Wouter Wynen, Danny McGee or me and you'll have a good starting point. Wouter and me have used the XXX rear suspension the entire season (albeit with CR hubs most of the time).