Did you know that the effective damping factor “delivered” to your speakers is affected by the impedance of the speaker cables? Before I quibbled about 80+ versus 400, I’d make sure that the impedance between the amp and the driver was down to about 0.1 to 0.4 ohms round trip. Two ohms round trip impedance in speaker cables would lower the effective damping factor to a point where you wouldn’t have the “good control” you're seeking over your drivers even if your amp had a damping factor of 1,000,000.