My car was built with the suspension upgrade(sub frame connectors, adjustable panhard rod, tube trailing arms, custome Bilstiens, lower and harder springs, larger front and rear swaybars), body kit (full lower skirts and rear upper spoiler and front air damn it)and Paxton supercharged. The Dr. I bought the car from was happy with the performance. Since I purchased the car it has been completely rebuilt with the following:
Vortec "T" Trim Supercharger with After Cooler
LT4 355 full motor (forged crank, rods, and pistons) Fully ported and polished heads
Aluminum Diff Cover
SLP Longtube Headders with Cat Bypass
Oil Cooler
Fully Adjustable Solid Bushing Front Lower Control Arms (The Red ones that match the rest of the suspension upgrades)
More aggressive Bilstiens
Baer Big Brakes (4 Piston 13")
Fiske 18" wheels 10 and 11s
285s and 295s tires
Racing Torsen Diff
The car makes about 475 (10psi) at the wheels with an automatic. I'll be changing that to a 6 speed soon. I expect a 4% power increase with that alone aswell as better car control. I am going to remove the ultra heavy power leather stock seats in favor of a set of Sparco Evo 2s.

I know the Dr. paid about $42K for the car new and I have since spent another $30K on it. Scarry a $72K Z28.

I know what I think its worth, but it is worth what some one is willing to pay on that day.