Errr thats a lot of miles matey!
Really depends if he is willing to give you garantee on it plus labour if its goes tis up!
Usually second hand units are alot less miles, as the engine blew up or it was a crash accident.
I would question why was it taken off at 140Kmmmmmm

Unless you know what the viens are like internally and the bearings and shafts are in good order its just scrap value!
But on the other hand it might be alright and cheap?
For a good one people have paid about £180-£250 but like I said you could pay more or less and still have it blow up!