HI - we replaced our retched thetford with a sealand traveler lite model - it was pretty easy and a huge improvement. The new one is made of porcelin and comes in a couple of colors. We had a tight space to put it into - and it was the only model that would fit. It comes in 2 heights and worth every penney we paid for it. Have your local rv dealer order it for you - if they don't have it in stock.
Off topic: I wondered if you would be interested in coming to the wa state mininrally this weekend - a bunch of forum members will be there - you can get loads of free advice. here's a link for info:
http://www.airforums.com/forum...ad.php?t=15675
pm with questions or e-mail - there will be other "under improvement" trailers there and we will be installing a univolt in 3Ms75argosy argosy trailer - on site.