This seems to boil down to a young guy vs. old guy. The young guys think it's cool, the old guys think it's dumb.
Young guys need to remember that most all of us old guys have been there. I've done some crazy stunts and mods on my vehicles, and it was only by the grace of Almighty God that I'm here today and the people riding with me are too. I think every old guy here can say that.
Twitch, the old guys just don't want to see you make a mistake that will haunt you for a long time. The back seat looks cool and, if I was in high school or college, I would think it was the cat's meow too. I could see myself sitting up there drinking beer checking out the chicks and having a great time.
Now that I own a house, have kids, etcetera, that thing scares the hell out of me. You make one wrong mistake with it and the dead kids' family will own you for the rest of your life. Not only will the guilt of what you did haunt you, but you won't have a leg to stand on in court. Every penny you make will go to paying the multi-million dollar judgment against you.
Of course, none of this may happen. People here have seen enough though to try to warn you off of this now, before someone does get hurt. Think about it. If you really want back seats, get something that has them from the factory. If you do decide to go through with this, well.... good luck I guess.