I think you have to make a distinction between killer dampers, like Penskes valved for the C5, and coil overs. The Penske's are where most of the gain will come from.
Coil overs are only going to help if you really need to change your spring rates or your ride heights (the spring installed height change is usually necessary when you change springs).
What are you trying to gain? Is the car too stiff? Is it too soft? If you are not certain, then you probably aren't ready for them.
It is one thing to have a tunable/adjustable suspension and quite another to know how to tune and adjust it. To that end, I suggest Carroll Smith's series of books on race car preparation. And the bible of race car vehicle dynamics - Bill Milliken's _Race Car Vehicle Dynamics_. Fred Puhn's _How to Make your Car Handle_ is a fine starting point.
And even if you have that expertise, you need to have track time to do the testing necessary to understand the impact of the range of adjustment (springs, dampers, ride height) available.
Also.. I would not buy coil overs unless you have access to a good set of scales ($1500-$2000). Because getting the corner weights correct after adjustment is critical.
Don't forget extra tires for this testing and a race trailer to haul all this stuff
The suspensions on these cars are already so freakin' incredible that few folks can drive them consistently to the limit anyway. And at the end of the day, the fast guys who spend all their time driving their STOCK cars usually end up whooping on the guys who spend most of their time tweaking their modified cars.
My goodness ... you must have a vandetta out for someone, - let's discuss you problem here ? Can we not be consumers, and purchase at will ? Can I not have a car setup for drag racing ... where in the world, do I come off as a "un-professional" as you are trying to hint? Let me have my fun, this is what it's all about ... buddy.
on my '90 Callaway. They were originally supplied to Callaway by Doug Rippie before he went to Eibach's.
Mine are on The FX3 fully adjustable Bilistein's. They are a full race set up with revalved shocks, Racing Eprom in the suspension module. Corner weighted, lowered. Stiff front and rear sway bars. They have Hyperco springs. I have the car set up currently for a Sears Point or Watkins Glen type course. I have done a lot of suspension work tuning this car. Infact it handles very similar to the stock Z06. But it took me 8 years to get it there.
The coil over shocks will help you tune the Z06 suspension and of course that is what all the World Challenge Cars and GT1/GT2 Petitie Lemans cars run. They are somewhat expensive but are infinetly tunable. You can not run them in any Stock class I know of and probably would find yourself bumped up to a class of race modified production or special built competition cars.
On the other hand if it made my '90 C4 Callaway handle like today's Stock Z06 just think what coilovers will do for a Z06!
How much money do you have and how fast do you want to go?