Tom:
You can attach directly to the Panorama cabinets if you want. You should use 4 screw mounting into the rear of the cabinet. Use the largest screws that work with the mounting plate you choose. Use 1" length. There are also a number of designs that are more of a platform, some with clamping arrangement. Because of the weight, you will need to make sure that the wall side of the bracket has enough holding power. That will likely be large screws directly into studs.
There are quite a number of on-line sources for various brackets, try googling "speaker brackets" or speaker wall mounts" etc.
Yes DR, a Maestro and pair of Titans should provide some pretty serious low-frequency foundation
