I'm about to look at a 2008 G 37 S Coupe, it has a 155k thousand miles on it and the guys asking 8500 for it. Is this fairbpricing, do these engines last past 200k?

 

Welcome to the site.
Sounds like a fair deal. The S Coupe has a lot of good upgrades from the standard coupe such as bigger brakes, better seats, LSD rear end, etc.
As far as the miles, they will last well over 200k w/ proper servicing & care but hard to say what that car has been through. Give it a good inspection and test drive and take it from there. If you want this as a fun second car that would be a good option, if you want it for your main ride for long road trips you might want to keep looking. For the long term, a motor & transmission rebuild would be something to plan for but these cars are well put together.
G/L and hope it works out.

 

I was looking forward to joining your ranks, the car was bought before I could check it out.