I don’t have the BMR K, but plan on it eventually. The only place they would cross would be at the rear-most point in the k-member — the K and the Steeda jack rails share bolts there.
I can’t see how they wouldn’t work just fine. The Steeda has a metal plate that slides under the K-member, and then the bolt goes through both. No reason to thing the BMR would be different than the OEM.