We had a older Chevy Tracker (same as GV) and now have a newer Grand Vitara. Love them both! I think starting in 2006 they have the larger body design.
Adding to what enblethen wrote, I found that the correct 4-wheel drive model for flat towing has a transfer case stick (older years) or knob on the dash (since 2006). I've seen alot of ads that say it's a 4-wheel drive, but it's not the kind that can be towed four wheels down (i.e. no transfer case knob on dash.)
You might also want to know that some years they only made 4-cyl and some years only 6-cyl.