This past Saturday, I went to an auction and on of the items was a 1988 K100 S(I think it was an S). It had the 22l trunk and side cases. Under each case was a conical shaped muffler similar to what might be on an airhead. It looked really nice from the back. The pipes split right after the header and one pipe went to the right side. This part looked kind of cobbled and appeared to interfere with the center stand. It did sound really good when it was running. Did any company manufacture this or was it a homemade item? It brought $1500, about what it was worth. The Cushman Silver Eagle next to it brought $4000.