1966 BMW R50/2 with rare 1954 Hollandia sidecar attached for sale

I have a 1954 BMW R50/2 with a 1954 Hollandia sidecar attached for sale for $13000. The engine on the bike was replaced with a R60/2 engine so it is not a matching number bike. It has a rare 8 1/2 gallon tank. The bike runs very well and the rig handles very well and tracks as it should. I believe the sidecar was built by Hollandia in 1954 as a police training unit. I had a vintage photo of one with two policemen and had a photo of one that another person owned here in the states but I can not find it. It is a very rare rig. I have a buyer interested in the bike without the sidecar so may be able to sell the sidecar without the bike for $4000. Sorry but I am not able to attach photos.