I've got an unrestored R51/3 in my garage. This machine is very pretty and tricked out, but, in my opinion, it's over restored. Chromed upper forks? Chromed rear spring shrouds? Polished motor? You never, never polish an old BMW (or Chang, or Ural, etc.) motor. It reduces the surface area. It will run hotter. It can also reduce the value of the bike. With old machines, originality is very important. $20,000.00? I've seen good, running examples for as low as $10,000.00 the average seems to be about $12,000.00 to,$15,000.00. I paid $6,000.00 for mine and It came with an untitled 1960 R60.I have seen an unrestored BMW R51/3 with an aftermarket tank go for $4,000.00 on CL, but that was a fluke. It was listed for something like 5 days before someone snapped it up. Also, those valve covers don't look right. I'm sure that model didn't have that central hold down bar under the valve cover hold down nut.