Shaun, same wheels as the ones we supplied on your Zed, on this link, on the Azure blue zed, which is lowered on Teins - http://www.350z-uk.com/topic/32711-rota-gtr-wheels-%e2%80%93-350z-fitment-from-cougar-store/
Sweet! Now that's easy to understand! haha You wouldn't know best offset for 350z to get rims sitting flush on wheel arch?
When we supply wheels, we tend to opt for an offset of 20 or as close as, have a look at our thread here, these all have an offset of 20 in the Rota GTR wheels we've supplied - http://www.350z-uk.com/topic/32711-rota-gtr-wheels-%e2%80%93-350z-fitment-from-cougar-store/
Offsets are measured in mm, and you're right, the lower the offset the further out the wheels sit, so offset of about 40 will be lost in the arch and an offset of 20 will most likely sit in line with the arch...
On the new set, the fronts will sit further out, so no issues with clearance but the rears will sit further in, there shouldn't be a clearance issue with the offset but they will sit further in than your last set...