If G35, search for the 2006-07 models. If I remember correctly 2005 and before had random engine issues, which issues were fixed post 2005 models. I do not have any experience with the G37 model, but I do prefer that model. Very sharp. My friend has a G35 that is his daily and he beats it on occasion and never gave him an issue. Windstorm, hailstorm, and floods never affected it (He is just lucky I think). I drove it a few times and I enjoyed it very much. I also drove the 2 door version, a bit sportier but rear seat access is not as easy. Depends on what your looking for.
I have been searching for one also, but balancing a nice used daily or a new tacoma once the wife's SUV is paid off.
Good luck on your search.