I had my 87 M6 restored by Korman Autoworks and they did a stunning job with the entire car. One issue is still plaguing us though. The brakes occasionally won't release completely and drag, heating up the rotors and causing a significant shimmy. They thought they had it fixed when they found a loose pin in the ABS control unit but the issue came back. Everything at the wheels are new and we have replaced the hydro unit. The issue got less frequent but still is there. Has anyone encountered this issue? The car is beautiful but this issue concerns me and makes the drive not anywhere near as pleasant.