There are two spoilers available through Spoiler Solutions
http://www.spoiler-solutions.com, one of which is pictured above.
This is where I found the info about it (it isn't listed on their site yet):
http://altimacoupeclub.com/vie...ae0b2.
As for getting the G over the a/c, why not then go for the 350Z over the G35 when the 350Z is going to perform better, if performance is truly the motive? There are always tradeoffs with those kinds of decisions, and, at least around here, most G35 and even 350Z drivers do no performance driving whatsoever and likely do not use the difference in performance that their rwd car is capable of anyway.
Personally I'd have considered a used 350Z in a heartbeat (it'd be great fun to attempt to exploit that performance gap with my meagre skills), but unfortunately living where it's winter 8-9 months of the year, the a/c made more sense to get as my only car. Not as fun, but funner than most or all fwd alternatives, and of course still affordable.