Personally, those offsets are a bit too weak. Check this out:
http://forums.g35club.org/zerothread/342067
The OEM offsets are 30mm for 18's and 30/33mm for 17's and you see how far they are sunken into the wheel well. Browse through that link and take note of the very aggressive and aggressive setups for the g35 coupe.
This website is also very helpful,
http://www.1010tires.com. Under the wheel tech category there is a wheel offset calulator. All the information needed for the oem specs are in the link above. Just plug in whatever wheels you are looking at and see how things work.