I don't know why my brother keeps throwing his money away on this car, he could have bought a decent 911 for what he's spent to keep it running. I think it's an '87 635 CSi and he recently added a "custom performance diff" which started making "loud noises" within five blocks of the mechanic's garage. Would you say this was an installation problem or a product defect? My bro thanks you for the advice:
