Questions to the W12 drivers…..

Hello guys, I’m not a Phaeton driver yet, but I might like to become one. For tomorrow, I have a test drive, and then there’s a decision. As part of the 1% campaign, I looked up a W12, year 12/2007, 13500KM at the price of 56K€. We don’t need to talk about the cost of leasing, there’s really nothing cheaper. What would I be interested in would be statements about the remaining costs. What about service costs (inspection)? Can someone tell me what such a service costs for the 12-ender about? How often does he have to go to customer service? How is the consumption in practice? I calculate this on average with approx. 16 – 18 L. Is this realistic? How is it specifically put in the 12er for reliability? Tomorrow, unfortunately, I can only drive the 3L TDI. Is the ride comfort transferable to the W12?