Go to Electrical updates/upgrades List

If you weren't constrained to keep it 100% factory correct, and intended to drive your old Mopar daily(within reason)
I pretty much already do. In fact it was my only car from 1993-2000.
Headlight wire upsize/add relays - safety
Relays go along with good H4 lamps. Now, maybe JW Speakers if I wanted a non-classic car.
Ammeter bypass/voltage gauge swap - safety/reliability
Not really. Mostly a mad idea that has been repeated ad infinitum.
It's not even the weakest link in the circuit.
One of the heavy duty modifications used with rear defrost and optional alternator and 'fleet service' is a better route.
Of course if one is unconstrained and going to EFI and a modern hemi then the whole power supply wiring needs to be a different design.
Electronic ignition conversion - lower maintenance/convenience?
Depends on the owner's perspective. When they work, they are lower maint., and setting dual point on a slant or a small block is a PIA.

You should skim through the threads here and see what things seem to give people the most trouble. I'd say a high percentage is ignition conversions.

For someone interested in rally, autocross or track time use, moving the battery to the trunk and adding warning lights to the oil pressure, temperature, and tach, are mods I'd select. I never did the battery in the trunk because I needed the trunk space.
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