We replaced our OEM mattress with an 8" Isoform memory foam mattress from Bergad.
www.isoform.com/ Our 2955 has a short queen and Bergad will do custom sizes.
This mattress is very similar to the tempurpedic (slightly firmer) but less money.
Pat had a spinal fusion done years ago and has never had a comfortable nights sleep since, untill now.
We have since purchased another for the stick house.
Rich
2004 GMC 2500 D/A, 2004 2955RL, Pullrite Superglide