My current Infiniti is a Q45t.
Not quite as nimble as a G (close with mods), but a bit more hi end and a bit slower 0-60.
I have been toying w/ the idea of a G35 for a bit, but this sites founder Dr Rex Birkmeier sold me this highly and professionally modified 1994 Q45t with 80k miles.
He is thinking about buying it back in a couple of years then I will probably buy a G35 sedan 6 speed (or maybe a 2 year used M45).
With your milage I can see your being hesitant driving it to hard.Be sure to follow break-in procedures to the letter, it <does> make a diference in the cars later life.
Fred...
