We have the 2007 Ford F53, so a few things might be different from MareFlos unit. We picked ours up in late 2006 and have been very happy with it.
1. Coach heat does two things, it heats the hot water heater for you (awesome) and you have fan control for high/low heat inside the coach. One vent is near the door, the other under the fridge. Works very well, in cold weather it really keeps the passengers warm if not to warm. Having hot water upon arrival is great.
3. None on our 2007, but it’s pretty easy to add a back flush I did this on my 2007. Once you take off the panel in the wet bay you have access to the side of the blank tank. Not ideal but enough you can flush.
4. From photos would be hard to tell but the sliding panels for the driver/passenger are double thick so they are wider and pretty obvious. I think the vast majority were dual pane and tinted. I’ve seen 10-11 over the years never saw one that wasn’t tinted.
