In-gear idle issues

I have a pn 8202. So it looks like it does not require one. With that said. I was thinking about it and I had the msd ignition box connected directly to the battery/alternator system. So the question is, being that the ballast and voltmeter have been changed out to no effect, what could be killing my voltage when I put it into gear, now that I am using the stock means of transferring power to the coil?

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Yup, that's correct. The 8203 does require one, but not the 8202. Cool.