ECU P4120534 Super Stock / Pro Stock / Nascar

That number comes up as the Chrysler Chrome box.
The description you give is like the Gold box.
(Gold box to 12500 rpm)
I used the Chrome box in an everyday driver. No issues.
The Gold box is a racing box to be used with a high power coil.

Does your car idle and drive under 2,000 rpm’s?