Hi Steve and welcome to the madhouse that is EuroKClub
If you have read the various threads in this forum on the K12 vs K13 debate you already know the answer.
I believe the concensus to be 'walk away'.
It is easy to get mesmerised by the looks, the performance and the comfort. But you will get all of that, and more, on a K13. The 13 is a MUCH better bike and the prices are dropping all the time although they can be hard to find.
If you can't resist, make sure that ALL the recalls have been done; a full service history doesn't guarantee that.