Just to be 100% percent sure, cause it sounds like you don't understand the reason for putting the Skyline and 350GT badges on I'm going to give you a bit of background. The Infiniti G35 is essentially the American market version of the Nissan Skyline 350GT. It is an 11th/(12th) generation Skyline, referred to as the V35/(V36) and released in 2001(2006) in the Japanese market. It (obviously) features an updated body styling from the R34 and comes in four(five) trims, the 250GT(and the AWD 250GT this is where the five comes from), 300GT, 350GT-8 and the 350GT Coupe. Of course, in America, we have things like, rev limiters and governors so that's why I say essentially and not exactly. There are some differences in the G35 as opposed to the 350GT. As for what's the difference in de-badging, re-badgeing or keeping your stock badges... it's more a matter of preference. Do you want to own the closest thing to a Skyline you can get without going to Japan and buying a true right-hand drive Skyline, do you like the clean look of no badges at all, or do you not really care? Me personally, I am swapping as much as I can out with the JDM Skyline parts, to include the Skyline 350GT badges, kick plates etc. I'm a huge Skyline lover, especially the R34's.
Gialla grill sites:
http://www.gruppe-s.com/350z/G35ext.htm
http://intensepower.com/gicog35cofrg.html
Also try ebay