Good Morning, We also have the 283 GTS and had to replace the mattress as it was terribly uncomfortable. We were disappointed that while it was advertised as a queen, the mattress size is that of a short Full, 54 x 72 inches. At home we sleep on a sleep number bed but found that to get one that fit the space and would go under the bottom of the wardrobe when the slide was in was very expensive. However, we found an alternative: The Air Dream Ultra Air Coil Sofa Bed Mattress with Integrated Air Controls (Mattress Size: Full 54 x 72). It is perfect for us. It is a coil mattress with an air chamber on top. It fits the space exactly. We deflate it to bring the slide in and it fits under the over hang of the wardrobe. Once we open the slide, we hit the remote and it automatically re-inflates. It is 11 inches thick fully inflated and we have a 2 inch memory foam topper on it for added comfort. The wired wand, lets us adjust the firmness with a touch of a button. Our only complaint is that there are no numbers on the remote, (so you have to go by feel) and it is one chamber of air, so you both have to sleep at the same firmness. This has worked great for us! Good Luck with your new rig, we love ours!