I looked at your galary pictures (nice truck by the way) but I couldn't see where the exhaust exits. Aside from making sure there are no leaks underneath I would exit the pipes out the back or to the side behind the rear wheels. You don't want those nasty smells swirling around and coming back into the cab, expecially with mama in there. A cat would be about the last thing I'd put on my 'bolt but to each his own. My truck is already green anyway.