You can use a few different OE type linear dampers with some modification. The physics behind the linear design is IMO better for road racing if properly installed than the rotary design as Rybo stated. I have the cheap OE Triumph unit on my Daytona with a heavier weight shock oil in it, and it works great. You can find good used OE dampers for $10-$40 all day long on forums and classifieds. That bracket set up for $30 sounds like a steal. Good luck.