Clunking Noise problems of the 2000 BMW Z3

I purchased car 6-4-12 after driving the car I noticed a squeak and a clunking noise coming from trunk, after removing trunk lining the spot welds [4] were broke loose in trunk floor from cross member where rear end is supported. . I took the car to dealer where car was bought hoping the dealer had a service bullition on car I was told they would repair car at my exspence I asked if that was an engineered repair or just a temporary repair there response was its the first time it had ever happened. . After searching the internet I found it was not the first time welds had come loose in the sub frame and if not repaired would cause major damage and possable control issues. This car is in excellent shape no rust issues at all was always garaged never driven in winter I beleave the subframe and rear axle mounting is under designed for this car. ## VIN passed ## BMW Z3m roadster 2000 ##.