Let me just say "BAD IDEA" alltogether. The M120 engine is huge and every aspect of installation into a 107 chassis would be completely custom as nothing would bolt up to anything or fit within the existing spaces. Assuming the impossible, that chassis is so under engineered for the weight and power of an M120 that it would be a death trap with one installed. You could easily buy a fleet of 129 600SL's for the cost of retrofitting M120 into a 107 chassis and making it even remotely safe enough to drive.