[Mark IV]

You need to shim the mount on the low side, leave the other side alone (although it will change slightly with the other side shimmed) and do use a good urethane mount. The urethane will allow less "rocking" and reduce the engine movement.

Bending the inputs to the side pipe will be difficult as they are welded to the collector and are a "unit". It would be easier to bend the header pipes "up" a like amount and allow that to reposition the side pipe in the opening.