I wonder if anyone ever uses the search feature at all.....but I have just posted this info YESTERDAY:
http://forums.corvetteforum.com/show...7&forum_id=101 You will note there is a response to my post by a C6 owner that took his rear 18x10.5 rear Z06 wheels from his 2002 Z06 with the following offsets and put them on his C6 (58mm rear offset) and said they worked great. I asked for pictures.
Anyway:
http://www.tomzwheels.com/FactoryReproductions.htm a forum vendor and HOUSE of Wheels has the 18x10.5 -58mm offset and 18x9.5 57mm offset wheels.
You have both posted incorrect info pertaining to offsets and possibly how they are measured. The stock rear offset on the C6 wheel is 79mm (not 73mm) and that is very recessed into the wheel well and it is for a 19x10 wheel. If two wheels have the same offset but different widths then they stick out different amounts because the offset is measured from the midpoint of the wheel. The center of the 19x10 starts at .25 inches away from where a 10.5" wheel's center is ...The math part:
19x10 79mm offset: 10 divided by 2 is 5 (for the centerline) minus 79mm (3.11 inches ...25.4mm per inch) equals 1.97 inches to the lip of this wheel from the hub (centerline).
So the 18x10.5 is: 10.5 divided by 2 =5.25 inches for the centerline minus the offset from the center (58mm) or 2.28" = 2.96" to the lip from the hub Which happens to be the very limit of what fits. If you look on your car you will see that this 1 inch difference is very apparent as the C6 wheels are recessed that amount.
Tire options include the 305 35 18 from nitto that is a zr rated autocross tire with the drag radial grip.
Good luck.