BaT has one right now. You could watch it to see what it does:
https://bringatrailer.com/listing/2018-bmw-m3-10/
One issue with listing on Bat (that I've heard, I haven't tried) is that there is a lengthy wait period to list. 6+ weeks, the last I heard. The market can change significantly in that time.
I agree with another poster that said just list it everywhere. FB, CarGurus, forums, etc.
Post your specs here, maybe someone will be interested. What are you trying to get in price?
Edit: My bad, I didn't see it's an M4. Most of the advice still applies, except for that auction of the M3.