Putting it in front of the back tire, like said before, is a BAD thing. It will most definitely discolor your rims, especially if they are aluminum. I can email you a pic of my friends truck with the Borla set up his rim is NASTY!
I have a side exit behind the back wheel, if someone will post for me I can put it up on here.
Everyone is right about the fumes entering the cabin. What is weird is Ford Explorers put their tailpipe going straight out the back and yet the back hatch opens. If you look at most vehicles that have a back hatch they exit the side. things that make you go, hmmm.