I'd stick with Corteco or use factory BMW, and replace both sides. Have you considered ordering them(corteco mounts) out of the states? You'll get rid of a load of vibrations and noises with replacing the engine mounts. I don't know how many kms are on the car, but you might consider getting it up on a lift and check the following:
1) lower control arms/upper ball joints
2) front axle cv joints
3) tie rod assemblies
Good luck with it.