Definitely don't pay their first asking price.
IMNSHO, a lot of Germans get ripped off bigtime with the quality and workmanship of their kitchens, at least the mid-level Küchenstudio ones. This is one area in which I've found that Fachladen do NOT deliver. My XH bought from a local family-owned place, thinking the service would be better. It was abominable. I didn't say much, b/c it was really =his= kitchen and he had it set up perfectly for his cooking comfort. But having grown up doing a lot of construction work, the shoddy installation really bothered me.
The last straw was that a plastic roller thingy in the dishwasher broke and every time he called, they'd forgotten to order the part. Finally I went in (wasn't even living w/ him any more) and sat on one of their counters until they ordered the part right in front of me. I told them I was coming by in 2 weeks. I did, and paid cash, and let them know he was moving into a bigger place and said I was sorry we as such small fish had bothered them for small maintenance questions. Apparently a lot of families are loyal to kitchen studios regardless of service, but a demanding American (ex)wifey-pie messed that up for them.
There might be guides out there on fair mark-downs for used kitchens. Do try spelling it the way Ruthie does when you
google it.