As far as I can tell, the F80 M3 never got fitted with a particulate filter but the F82 M4 did towards the end of 2018. I've found an M3 I like the look of, high spec and an individual colour. The only downside is that it has slightly higher mileage than I'd like but it should be a long term car and given I don't do many miles shouldn't be too much of an issue as long as the condition is excellent.