For the Corvette Coupe reported to be a cheaper model I will believe that when GM says it. I could see the General making a dumb decision like this, they have done it in the past with the FRC (it was about 6-7k cheaper than the base Corvette). As for the ZR1/Z06 I have not seen an article where they have claimed one will have boost, and one will. I don't even know if there will be two separate models for sure or what they will be called. If you have seen any of this from GM, please point me in the right direction for I have been slacking.
In the higher performance models it would be sweet if they brought back the moniker LT5 and I wouldn't be opposed to having another DOHC Corvette motor... if it made the right amount of power!!
This would be my guess