The M120 is pretty much 2 inline 6 M104 engines stuck together. The M104 2.8 and 3.2 from 93 ish to 99 use dual ended coils ( one end on a plug then a wire to another cylinder. ) To make this work you would need to change valve covers.

The ECM drives ( ignites ) the coils.

The coil connector is coaxial and I don't know where you can get them other than clipping a harness.