The front needs a 17 x 9.5 +56mm offset.
The rear can be either 17 x 11 +36mm offset
or 17 x 9.5 +38mm offset. The 11" will be a perfect match to the front on offset, the 9.5 will be set inside by less than 1/4", so no spacer will be required.
As for OEM vs. Replica; you can shop around for OEM but if you find a set in perfect condition they will be expensive. You can find some less expensive but ususally they show their age. The replicas I sell are by Original Equipment Concepts (O.E.C.) who was one of the OEM wheel suppliers for the corvette so you know the qualitiy is good. They carry a lifetime warranty on the structual and the price is right. Let me know if you need prices.
Jim Longwith