Older Z's are more like 13.80's- 14 flat.
I'm surprised you beat him so bad, but even if you two had been side-by-side, he still would've lost, so who cares. Nice kill....
I've spent over an hour looking at road tests for the 2004 GTO and the 2007 350Z, the 2007 350Z Nismo and 2003, 2004 and 2005 350Z's. I've look at Sport Compact Car, Road and Track Car and Driver, Edmunds, MM&FF's, I can't find anything different than what I posted, which was this:
2003-2005 350Z, 350Z Nismo R Tune and 350z Nismo S Tune are 14.0- 14.4 1/4 mile cars.
The 2004 GTO is a 13.5-13.8 1/4 mile car. I know some people have gone 13.1 with them stock, but I'm using mag times because that eliminates the variables.
The 2007 350Z and the 2007 Nismo 350Z are 13.6-13.7.
So the car he raced, a 2007 as stated by the OP is a drivers race with the 2004 GTO, and with his mods the GTO gets the upper hand.
So we don't get into a pissing match, can you please post some links to a reputable source for these claims. If you would like I can post links to my claims.