I just picked up a new DX4R pro.

I then emailed Protek/Amain and asked about the Protek transmitter case with changeable foam inserts.
From the pictures of the DX3R foam, you would need to cut out a portion of the foam and this will interfere with one of the storage pockets in the foam.
Protek said they have new DX4R foam in production and are expecting stock in soon!