One of the problems with the stock seat was butt burn after 80 miles and the pillon looked like a hunk of cheese. The seats are covered in vinyl and the seam along the edges of the rider seat dug into my thighs. Other than that it's a great seat, lol.
Abe Ramos of Poway, California took my stock Yammy seat. He ripped off the stock covers reshaped the foam on both the rider seat and passenger pillon. In the passenger pillon he built up foam using progressively lighter weight foams. He left a center well in the passenger pillon and he filled that well with 1/2 inch of seat gel. He covered the gel with a layer of foam and covered that layer with polyester padding to round the pillon edges. I wanted my pillon to have a rounder profile and no sharp edges to bite into my passenger's legs. He recovered both seats with genuine matched leather hides and they look really sweet.
If you are interested in having Abe rework your seat, he does all kinds of bikes, seats, and materials--email me and I'll send you his cell phone number to call him and make an appointment to discuss your seat. As soon as his home computer is working I'll get his direct email online.