My choice wouldn't be everyone's choice. Among the many charms the Z has over your modded C5 that trump the C5 -
is the uniqueness. (Nothing so special about a supercharged C5 or C6. You see them all the time.)
And, for the money spent on purchasing and then building up the C5, one could have their Z and the ponies too. Think about that!
I'd sell the C5 and turn the money around and give a chunk to Pete and AES for a closed deck 427 LT5 and never look back - except to see rivals in the rear-view mirror. But! That's just me.
Oh, and as far as parts scarcity goes, the REGISTRY takes car of its own. Parts and expertise is made available, and talk about lack thereof is highly
over wrought.
Welcome to the BROTHERHOOD OF THE BEAST!