Yeah actually the electronic spark control works pretty well. All the 80's carb 2.2's used a computer controlled ignition timing system and they ran well with it. Downside to the ESC is you can't just go and recurve your distributor to get a different timing curve like you can with a conventional.
Lean Burn only existed in the latter half of the 70's. After that it was just Electronic Spark Control. So many people look under the hood, see the ESC computer hanging off the air cleaner and think they have Lean Burn, even tho the car does not say Lean Burn anywhere on it anywhere.
However, the OP has a car that originally had the early 80's fuel injection that chrysler put on their imperials. The early fuel injection was allegedly problematic and your Fuel Injection system was replaced by a carb many years ago, by the dealer most likely. EFI models also got Electronic Spark Control. If you do change over to a different ignition setup there is no need to change your carb. After the death of Lean Burn in the late 70's, carbs were no longer computer controlled. Because of that, there's no need to change carbs when you change your ignition system.