Purchased a used V300 system from a TD racer and since he ran a mag I need the interface wire from the MSD tach terminal to the V300.
Racepak has a wire that is $$20.
Is this just a wire that goes to the Moledx 3 hole plug or is there some sort of Racepak magic in the wire? Racepak PN 280-CA-HARNMSD3

You are correct Bruce. It's just a piece of red wire out of center pin on the Molex connector for the V300sd. You can get the connectors and terminals from Mcmaster-Carr which you might need for other parts of the V300sd.

There is a software setting required to change the number of pulses on a mag to regular MSD ignition too.

Thank you Greg.
Pricey stuff these cables.

Greg is the mini TRS plug to DB9 cable a standard cable that can be bought at Best Buy or is it a proprietary cable from RP?