Hi E46 M3 Brothers - The guys at BMW of Nashville somehow ended up with an extra Dinan 3.91 diff when they got mine. I'm told to say they will make someone a smoking deal on it. Also Dinan has a 15% rebate on their parts until the end of April. That's why I've went ahead with my upgrades the past month. If anyone is interested they need to give Jim in BMW Parts a call at 615-850-4040. It will fit a standard E46 M3 manual transmission or the SMG. The SMG will require the Dinan transmission software. Standard disclaimer: I am non-affiliated with BMW of Nashville or DINAN other than as a customer. Cheers.