duodeluxe,
I'm sorry but I don't see much difference in how one should takes care of a customer whether they sell them a new unit or a used unit. The major difference is in the GP associated with each type of sale. Any issues with the factory on new equipment should remain as conversations between the dealer & factory. Certainly, used equipment was first brought to the market place as an end user purchase or financed unit or dealer rental fleet - STR or LTR as a new unit which later turns into a source for future used. Good used equipment can be hard to find unless you grow your own and the devil you know is usually better than the one you don't know. And most used equipment sales are dealer "reburbished" or "reconditioned" units.