99 XJ ECU Swap Question?

[XJJeeper59]

I purchased a "Backup" ECU for my trip to Mexico "Just in case". My existing ECU is a 493AE (California) and the replacement is a 492AE (Federal). I know there is some differences because of State vs Federal, 1 cat vs 2 (I have 2 cats), O2 sensors etcetera.
If I just SWAP the computers to see if the "Backup" one works, Can I SCREW up anything? If it does not run properly with "Backup" will replacing the Original bring All back to Normal? Thanks, Sean San Diego

 

[Saudade]

According to my parts guide 492 is Federal and 493 is California. Does your XJ have the Emissions sticker under the hood that says it's Federal? How many O2 sensors do you have?

 

[XJJeeper59]

I crossed my Numbers, your post made me look again. Existing is 493AE (Cal) replacement is 492AE (Federal). Emissions sticker states 99 California Compliant.
Hate to say. but I live in Comifornia, XJ is from Cal. 2 cats etc.Just asking if I swap for a test could it mess up anything? Thanks