As for the damper thing. I've heard this before on the FC RX7 that had such a kit. Yes they had a specific part number... and we could not get any valving information from them. We had to dyno them ourselves to find a very wavy and inconsistent curve. Those were replaced with a set of 8610 Road race inserts in that car (the customer's choice, he's a pretty smart engineer who designs fun government stuff).
I've been doing lots of testing too, I've had coil-overs on my car since about 2 weeks after picking in up on 6/2/12. I found that I don't need anything custom damping wise with the range the stuff I picked has... and I get a lifetime warranty and stainless steel bodies too.
Also let's not forget that some companies have even tried to make their own shocks, and that didn't last either. I've been through this with various cars, RX7's, Mustangs, you name it. In the end my track record, personally, is pretty damned good. I used to sell the brand being talked about here, I stopped despite it being something that I didn't have to work hard to sell because I was sick and tired of being bucked on what I wanted for spring rates and ridiculous long lead times. I even started buying indirectly hoping the other company would have better luck. Nope. Now maybe things have changed on that front, but the simple fact is we all sell parts. We all want you to believe what we do is best, myself included. I've just been around long enough and see enough of my customers face to fact at events to know that I have to justify what I do. And what better way is there than proving you can win? What else can I do? The proof is in the pudding, no? I don't like a rear high rate setup, but others do. Ok... I'd say that each customer needs to think about things carefully and consider why each shop is doing what they are doing. Maybe even TALK to the various vendors to gain some insight. I'm glad to explain why I do what I do... and I bet when you hear it, it'll make perfect sense.