After reading a lot of input here, we decided not to cut our 2004 Tuscon roof for a factory type unit and potentially have to deal with leaks issues, and roof support costs. We decided to install a 12K-BTU unit on the front wall to utilize the front frame for support. After removing the front wall paneling I was surprised at the lack of any real wall framing, just some scabbed rips of OSB glued to the back of the paneling at millwork anchor points, some of which were only partially attached. After choosing the A/C model, I framed the rough opening for the unit allowing some clearance for metal flashing and sealant. I raised the rough opening to clear the bottom sill plateof the wall. The Tuscon also has the angled exterior wall which complicated the framing some. The top and bottom of the opening are lined with the bent over metal siding. The sides are lined with aluminum along with corner flashing all sealed with urethane sealant. And anodized corner trim on the outside of the opening. Here are pics of the framing (with a 4 degree slope on the top and bottom to lock the unit on a slant for condensate drainage). And a pic of the finished opening. I am waiting for the sill pan fabrication which will extend from the inside bottom edge of the A/C to the outside of the opening and shed any condensation to the outside. I will follow up with the final project pics.