The "modifications" he is talking about is to keep the sub-frame, shock towers and strut towers from tearing out of the car. I guess you could wait until they fail, but that is ridiculous. With the M3, BMW fixed the problem. The repair pieces are available through BMW. They don't provide any advantage other than being able to keep the tub from coming apart.

Are you allowed to fix a chassis or do you have to throw it out when something happens to it?