A good place to start is either Calmini (http://www.puresuzuki.com/sidekick_tracker.htm
) or Rocky Road (http://www.rocky-road.com/sidekick.html
). Both of these companies have lots of stuff for the Tracker/Kick/X90/Vitara platform. You should be able to find a kit that will benefit your needs, a mild lift to fit some larger more aggressive mud terrain or similar style tires. Maybe some lower gearing depending on how large you go on tire size.