A while back I had to replace my tank, (in the floor) I ordered a replacement one made by "Sunshine Marine Tanks Inc." After removing the old tank, I measured and sent the specs to the tank company and when I got it in, I wnt over the measurements and they were right on spec!  Since replacing the tank with a new one I can't describe the feeling of confidence knowing the condition of the tank and below deck components.  I don't advise on used, there are several good tank manufactures out there, and while it may cost more, (not a lot) than a used one, it will definitly last a lot longer!!  
 
