E46 diff mountings

[Midnightclub]

You can buy a subframe reinforcement plate kit, basically they'll repair the cracks as best they can and then weld the plates over the top. Generally they'll fill the cavity with reinforcing foam to help stop the rear end flexing.

That's if it isn't too far gone, could well need a whole new rear floor welding in which tbh it would be worth getting another one as it'll be cheaper than the repair job