I bought the SH pipe and springs. I just went to fit it tonight, and the springs they sent are shorter that the original KX500. They won't go anywhere near! Also, the U shape cooling pipe rubs on the inside of the pipe. Going to need a bit of "adjustment" there I think...
I'm off to the local sled shop on Saturday morning. It's a big main dealer for Arctic cat, Suzuki, Yamaha and Harley, so I might get lucky. If I do, I'll try and post up a part number.