A high-flow intake kit will net you the same effect and will range in price from $150 - $400, depending on what you go with. Aside from that, nothing has been developed yet. The BOV is louder on the F56 than it has been on older gen MINIs.
I added a NM Engineering Intake and NM Engineering Power module and the BOV is loud and clear on my F55. The weekend add an Remus Alxe back exhaust should make it sound all good all around and some enhanced performance to boot.