Gray market question

[Broadside Bob]

Hi all, I'm looking at purchasing my first Rolex from a local gray market seller. From everything I can tell, they have a good reputation on the forum and locally. I'll be buying pre-owned. They claim to service every pre-owned watch the sell to make it indistinguishable from a new watch and guarantee the watch for 1 year. Of the watches I looked at there, 3 out of 4 came with papers; that is one of my requirements.

Is there anything specific I need to be careful of? Assuming no aftermarket changes have been made to the watch, will Rolex still service it? This particular seller will also service the watch down the road (at my cost) and claims to do the work significantly cheaper and faster than Rolex; is there any reason to think that regular servie from Rolex is superior?

Sorry for the newb questions, but I would apprecaite any input.