Buying new one, Where? when?

Prices are still down about 10% ( asking prices ) from where they were about 6 months ago. November or December are the best months, any salesman will tell you that. Your about 6 weeks too late. Volvo's are so much better. Arrow had a bunch of 670's they had to move and they were in the high $40K's. 300K miles, that's a steal. Now the ones they have left are in the mid to high $50's.
You would be a much happier O/O with a D13.

You should check PENSKE if your going to buy used. You can work an awesome deal with them, and no one on the planet does better maintenance, and keeps better records of it than they do. They offer a complete 2 year drive train warranty for a few thousand also.