In regards to the mid-engined Corvette, I think that it will be underwhelming.
GM, like Porsche and the 911, has had 50 years to evolve and perfect the Corvette's front-engine configuration. I doubt that they have the engineering talent to create a world-class mid-engined sports car straight out of the box. Maybe they'll prove me wrong?
On the other hand, Porsche has had a 20-year head start designing mid-engined sports cars with the Boxster/Cayman and the mid-engined 911 is already designed and being tested:
http://986forum.com/forums/zuffenhausen-lounge-happy-hour-after-17-00-somewhere/65197-pics-911rsr-mid-engine.html