[moneymanager]

Others will chime in but I wouldn't call CIS an improvement, especially the early versions. Over the years a lot of bells and whistles were nailed onto the original design in an effort to make an acceptable product. THis yielded a device at least as complicated as a Weber with little ability to fine tune it, middling performance, but decent for the era emissions. With the advantage of history, i'd give it a C+.
Switching to CIS and changing out your cams so the car will run decently will cost at least $5k, and likely more when you get into all the "while I'm in there..."s...in return I'll bet you save $100 a year in gasoline.
If I were thinking about the changes you are seeking, I'd be looking at some sort of modern injection system for better performance, emissions, and economy.