You can find a ton of people on Ebay selling immitation dash kits. If you go that route, be very careful, as there are so many different ones for C4's and most of the time they seem to have the wrong one listed or some other weird description (like 95-97, which obviously couldn't work). I considered that option when my console started peeling, but it just didn't look right so I sent it back.
The shifter knob can be found in most of the vette catalogs (MidAmerica, Ecklers, etc.).
I never checked on the engine parts, but I'd imagine if anyone has them, it would be these catalogs.
Good luck if you decide to go with them.