Well, it depends on what you want to do...
Daily Driver? Offroading?
Also, are they 2-doors or 4-doors? eight valve or 16 valve (the '92)
The 98 would be my choice for a daily driver (too new to fab on or subject to an offroad beating) and the '92 would be a nice offroader/daily driver as it won't kill you if you break it on the trail. Either can be modded for the trials and the '98, I believe, has a bigger engine (?) I think there is a page here at Zukiworld that has the specs for the various years of Tracker...
my 2 cents...