I have regular access to a G35 Coupe and it is indeed a nice car. Firm ride, powerful motor, execellent handling, and good looks. The back seat is useless for adults and marginal for children.
Of the cars you are considering, the S4 is without a doubt the one to get, if you can afford it. In the world of sports sedans, it shares the top of the pedestal with the M3. The S4 has awesome performance, low-key looks, and a beautiful interior. The back seat is quite cramped, though. Still, it is a car to be admired by anyone who considers themselves to be an automotive enthusiast.
Lee K
98 SVT, silver
03 Evo, red