You might look for a used Mopar Performance OBD-II PCM for years 1996+

The old magazine ads claimed 20+ torque gain.

I can remember reading posts back in the 1990s where Magnum 5.2 owners tried out MP PCM’s for 5.9 engines and reported that they ran without hiccups, but I do not remember anyone commenting on fuel economy changes.

These companies that repair Magnum PCMs ought to be able to flash the data tables for the MP CM onto an standard OEM unit.

I have a 1998 to 2003 Superchips Micro Max tuner for Ram pickups that I bought at a yard sale for $25
but it says “VIN Locked” when it powers up.
This Superchips unit seems to be able to read and erase DTC codes for any Chrysler OBD-II vehicle.