What am I missing on GVWR??

Also, in Europe at least when they use a cassette toilet it usually comes with a SOG kit,

As far as I know, there is/was a "disagreement" between the SOG inventors and the RV toilet suppliers. None of the RVs by the major players here come with an SOG installed, they are always retrofitted or dealer installed.

I agree that Heki and Seitz products are overpriced for what they offer. But for a long time, they were considered "state of the art". I read that current Northstar campers don't use them any longer.

The appliances are a sad story, really. All manufacturers have to order from the same pool of products, and quality appears to be getting worse every year, while innovation is slow at best. The kitchen fan in my Northstar is a joke. The range oven quit working reliably in the second year. Can't really blame that on the camper manufacturer. They can only install what they can get, and I hear the smaller manufacturers have difficulties getting their supplies at reasonable prices. There are higher-quality product lines, but if installing them prices your product out of the market, what are you going to do?

Wood vs. Aluminum vs. Fiberglass vs. Sandwich is an age old discussion. Might as well make it into a religion. IMO it is out there with "gas vs. diesel".