How do you determine kV and Ohm for BMW coils?

[CMG]

This is a general question relating to all the 80's bimmers that have the coil ignition system. How do you determine the kV and ohm for the stock BMW coils? I tried searching for a chart or some kind of info but no luck. I'm just checking out options for various aftermarket coils. I use larger low resistance plug wires so is there any benefit to getting a coil slightly higher volt or slightly lower ohms? Is the distributor going to be the limiting factor? I'm not an electrical engineer so forgive me if these questions are kind of ignorant.

[Kershaw]

No idea and apparently it doesn't matter. The Bentley states that the spec is .5 primary / 5000 ohms secondary and anything higher should be replaced. But Bosch decided to change what the new coils spec at to .7 / 7000 ohms. Confused, I bought two because that couldn't be right. I also now have like... 3 or 4 used coils with varying spec in the basement. They all work just fine.

So make up your own rules and do whatever you want. Apparently.

[CMG]

Hmm, yeah I'm aware that is the number if you are testing coil function. I'm just checking out various aftermarket coils and they have options for different kV and ohms. I don't believe a lower resistance would produce much benefit due to the limitations of the rest of the ignition system, and a higher output might fry the rest of the ignition system.
My thought process in general is that there is not a lot of info that I can find for upgrading ignition other than larger lower resistance wires and different plugs.
I've just been reading various things for years on different aspects of ignition. I guess the bottom line is that it doesn't make a huge difference for the average car, but some of my cars will be seeing high boost levels so for them I've seen tons of different options for lowering resistance and earthing/grounding them, and I'm trying to self-educate myself about it and do some experiment for one, and prevent a grenade for two.

[wilholl]

I think you might be overthinking it a bit, just my opinion.
the average e30 and most modified ones will be fine with the stock ignition in good condition.
Heavily modified and boosted will need upgrades and or stand alone systems.
The ratio is typically what determines the output voltage, ie;
.5/5000 , .7/7000, each should produce approximately the same output voltage

[CMG]

Haha, you must be a psychologist, I'm always overthinking things.

[wilholl]

Haha, you must be a psychologist, I'm always overthinking things.

No,... just old