I have a Kerker, I am asking $150 for it, plus actual shipping costs. I ship things for a living, I know the best and cheapest way to ship things.
It is exactly like the video above, except it doesn't have the little reverse cone at the very end. It has a flat end plate at the end instead of the little reverse cone.
It is in very good shape for a 30 year old system. No holes. A little scraped on the bottom where no one will see it. A little blued near the exhaust ports. A little very light surface rust, nothing bad. A little more rust at the flanges where they bolt to the engine, but clean-up-able. There is a scrape at the end of the muffler, but it is low, and not real obvious.
In the video look at the funky rear mounting strap -- I have that too.
I did some research, and this is a pretty awesome exhaust. This was the performance exhaust to have back in the day, and it probably still out-performs most or all modern 2 into 1s. It even has a small cross-over tube near the flanges. I have never seen an aftermarket XS650 exhaust with a cross-over tube, other than this. Actually, the cross-over tube is missing, but the fittings are there in good shape, so all you will need is a little piece of pipe and two pipe clamps.
PM me your email address if interested, and I'll take pics tomorrow and send them to you.