2 years of street and Heavy track use and my DBA 4000's finally gave up in spectacular fashion.
I used these on the street with the Carbotech Bobcat pads and on the track with Carbotech XP12's the first year and Cobalt Friction XR-1's this year. They never warped and always performed as expected. I loved them and they will be missed....
As others have mentioned, I highly recommend the Cobalt Friction Pads. Not only do they work FANTASTICALLY on the track but their customer service is awesome. If you have not tried them yet please do, you will not be sorry.
I am now looking at the ROI of 6 pot CTSV/ZL1 front brakes or the Z/28. Since I basically use my car at the track more than the street, or getting to the track, it kinda makes sense to me.