I think what you are looking for requires a great deal of displacement in the cabinet. While the P10's go down to 19hz, they do not move air like a speaker that has much more cabinet volume.
In the comparable price range of the Piega P10, I would highly recommend the Talon Khorus X. It is a stable 8 ohm load at about 90.5 db that moves quite a bit more air than the P10. Make sure if you listen to the Khorus X that it is not an upgraded Khorus and it has at least 1000 hours on the speaker.
The Verity is a gorgeous sound, but like the P10, will not move the air like your brother wants. For most people, either of these combinations with the Tenor's are world class. Your brother must really like hard driving music.
In the comparable price range of the Piega P10, I would highly recommend the Talon Khorus X. It is a stable 8 ohm load at about 90.5 db that moves quite a bit more air than the P10. Make sure if you listen to the Khorus X that it is not an upgraded Khorus and it has at least 1000 hours on the speaker.
The Verity is a gorgeous sound, but like the P10, will not move the air like your brother wants. For most people, either of these combinations with the Tenor's are world class. Your brother must really like hard driving music.