I'm right there with you regarding building a faster car for less. It's very much so do-able. Just like all the ZL1 guys can add a cam, CAI, LT headers, and pulleys to make-up the 300lb weight difference. OR just order the brake kit whenever it becomes available, and order the lighter rear-window. The glory if today's era is that while we're stuck with one engine block, there's no stopping you from doing whatever you want and ending up with a car that fits your needs and your wants.
I just can't wait to hear that whine of the supercharger on my ZL1. Plus, even if a Z28 is faster, i'll let him beat me once. After that we'll just go hunt mustangs together