I bought these from a friend for my c5, but decided to go a different direction. They are stock c4 zr1 wheels with tires. The front tires have about 65% life and are 225 50zr 16's and the rears have about 20% life left and are 335 35r 17's making it 17 x 12 wide with the tires. This is a great deal for wheel and tire combo. Asking $700 shipped firm, local pickup is also available at a reduced price. Pm me with any questions!! Thanks for looking.
Here is a shot of the rear of my c5. The left wheel is the zr1 wheel and the right is my stock c5 wheel. Just showing the difference in width.