A while ago I was trying to find the difference between 2 coils that are listed for a 97 M104 engine depending on what body it was installed in,( still have not found the differences, the spec sheets are the same )

At some point I came across a notation of an internal permanent magnet used in ignition coils ( don't recall if the M104 had them or not )

Apparently the magnet adds sparking power and reduces coil size. This is one of those things that are not apparent when just looking at a coil and might be buried in some text somewhere. The patent listed below is from 91 so the technology is pretty old. I wonder if the magnet causes any delay in forming spark or any other odd issues?

Patent US4990881 - Ignition coil with permanent magnet - Google Patents

While we are on the subject of coils, in the mid 95's there were spark plug wires called " Nology " these had capacitors in them to supposedly boost power. I'm not sure if they actually worked, but the amount of RF they put out was enough to trip light beam sensors and generally cause all sorts of electronic equipment problems. Anyone ever use these?

If you are after improving spark then there is really not much to do. The factory coils are very high output. All the Bosch coils and wires for these are pretty darn good. I do use an iridium plug in my car mainly for the kv requirements to get the spark to jump with boost.
The coils for the m104 all update to one part. The originals ones were bremi or beru. And later went to the bosch. You can only get the bosch ones now which are the best.