Long story short (more to come in Engine talk later):
At annual we decided to change the old harness with New Horizons harness.
After the ground run once the annual was completed, we had a finding that forced my hand to buy a new engine (it was a high time engine anyways).
The new engine came from TCM with new magnetos and harnesses. I decided to replace one of them with a Surefly electronic ignition.
So:
Brand new TCM magneto, S6RN-1225, p/n 10-349350-5: $1500
Brand new TCM harness, 10-423684-1: $500
Brand new New Horizons harness with elbows: $600

To be specific, the TCM magneto and harness have on them 1-2 hours depending on how long the factory ran them on the stand.
The New Horizons harness has less than 20 minutes on it.

If the magneto and TCM harness get bought together, I pay shipping, otherwise buyer pays shipping.
Thanks

Hi Stefan,

I would think an IO550 is an IO550... not sure how customized harnesses are. Would you think this would fit our V35B IO550B4F? Am local so can meet up once the winter storm passes.

It's an IO550C.
Do you mean if the magneto would fit the engine or the harness?
The harness is magneto specific.
The New Horizons harness fits the Slick magneto.

So that would be the harness required for the Surefly?

That’s correct, the New Horizons harness would fit a Surefly.

Magneto sold.
Remaining are the TCM harness for a Right magneto, p/n 10-423684-1, as well as the New Horizons harness for a Left magneto.

Made a mistake in the price of the harnesses.
The New Horizons harness is $300 since it is only for one side
The TCM harness is $250.