http://audio.com.pl/testy/stereo/zespoly-glosnikowe/284-focal-chorus-836v
This actually IS a speaker that could benefit from bi-amping, but with no terminals for it, you are stuck. What these speakers need is unusually beefy amps. Not high in power, but with excellent low-impedance drive.
I would suggest among the best values are the Parasound A23/A21 amps in the linear area, and Hypex or nuForce amps in the Class D range. Look for amps that can drive 2 Ohms.
Best,
E