2001 S3 Thunderbolt ECM question

I have a 2001 S3 Thunderbolt with no spark. I believe it has a bad ECM, altough I am not 100% sure. The ECM #s are BFIUS1 N0306.QA00068 US16KA210.
What is interchangable and what happens if I get one that the N0306.******* number and US1****** number are diffrent then what I have? Is the only option a used one from eBay>
Thank you

Anyone have any ideas? Thanks

Why do you think it is the ECM? Have you checked the crank sensor, plug and timing cup?

Have you checked the ignition relay? Fuse? Did you check the sidestand switch? Clutch switch? Neutral switch? Is the ECM getting power?

If you really need an ECM, IDS should be able to help.