Wow, that really sucks, I feel for you... It seems very obvious that a previous owner was EXTREMELY HARD on your car... But you may be getting toward the end of the damage, and with a fresh driveline from the clutch-on-back, many many miles of trouble-free driving...
I bought my '06 M6 with 9,000 miles on it.... From a 65 year old retired dentist... I've had no problems.
