RE: What goes up.....
If it's the Big Swamp Buggy I don't believe you'll have any luck getting it straight - the way these are made it is tough for them to warp at all. However, if it is a regular Swamp Buggy you may be able to try the suggestions above. On the other hand, it may run okay with the warp, so if you cannot straighten it out, try it first before giving up.