A customer has added MAJOR horsepower to his car….a full VF supercharger kit, Stage II, and was concerned about the abuse that his car could now endure w the new installation. So, one of the pieces to be attacked was the rear sub-frame, known as a soft spot on the frame of the E46 M3 (and earlier models as well).
To do this, the full rear suspension needs to be removed from the car, and to do it right, the gas tank as well. Then, the area needs to be fully prepared prior to the welding of the new subframe supports. In addition, to ensure that the new support mounts are properly mounted, you need to take the inner trunk area out, and cut thru the top portion right above the differential, to reinforce the top of this area as well. This ensure that both the top and bottom of each area have added plates, and full seam welding, and you drill thru the plates to allow rose welds to be added to ensure you have thru contact. We then painted the area w heavy duty rust protection, and then paint themselves, to ensure we have a solution that can last and take all the abuse from daily street use in all weather conditions.
There is currently a class-action settlement concerning the E46 subframe. (http://www.e46subframeclassactionsettlement.com/)
Wow What a nice discuss about BMW E46 M3!