I'm sure I will have lots of questions for you all eventually..like here's one I just thought of, has any one been rear ended? Does having the tire on the back cause the whole window to shatter? I thought I heard about that somewhere? Would a bumper guard help?

Yes the rear window will shatter if the tire is hit.  A bumper guard would only help if it sits out far enough to stop the tire from getting hit.  All the ones I've seen wouldn't help with this.

Goegre

I got rear-ended in my 2001 Tracker and all it did was push the bottom of the tire in, no broken glass. I think it all depends on what hits you! I got hit by an Astro Van that was doing about 35 mph(speed limit on street, no braking, I was stopped behind garbage truck).

I have been rear ended twice, and both times it was minor and low enough to hit my bumper.  All is well except for my tow hook which go bent down slight more.

Still pissed as hell that it happened.