Upgrading Ignition system

Easiest would be the ready-to-run Ningbo distributor plus e-core coil on ebay. Since only $70 total, you could afford to carry spares in the trunk. But, sounds like you want to spend more and there are many solutions (red, yellow, ...) to take your money, though perhaps not appreciably improve the spark. Anything which requires a ballast is old-fashioned electronics. For the very best spark control, you need an electronic box like megasquirt, megajolt, Holley Commander 950, or such. Ideal would be with an LS coil per cylinder, but that would be a custom design.