SAR regulation requires you to file a SAR if you suspect money laundering or a "Federal criminal violation." Since you're already working with your legal team, I think their opinion on the applicability of this could deserve some attention. The fact that you've been filing and would stop leaves you open to some criticism, so potentially talking to your regulators or FinCEN* about your planned decision not to file, it that's what you choose, could keep you ahead of it.
*Not that I think FinCEN or any other regulator would give you concrete guidance saying one thing or another, but sometimes documenting that you called them and they didn't object goes a long way.
My opinion is that I don't think I'd file, but I think it's a good question and you need to be clear when you document your decision.