Seems like a good plan to me. I am having similar thoughts about Hyundai's new RWD coupe. Its nearly as fast as my G37, looks better on the outside, and my payments would drop by 1/3. I just don't know if I want to take such a step backward in terms of luxury....
2010 Infiniti G37S 7AT graphite/black w/nav
2006 Lexus IS350 white/black w/nav
1997 Ford Expedition Eddie Bauer