Rooze...I understand that you are operating the amps bridged (1600 watts!). You should realize that each channel is operating into 2 ohms, and while the amp is built to withstand this environment, I think that fidelity is somewhat degraded relative to what it will do into 4 or 8 ohms. I suggest that you experiment with using only one stereo amp for the pair of speakers, and compare with bridged results.
In the long run, I think that you might do better to use the amps in a biamp configuration using an electronic crossover. That is what I do. One channel drives a subwoofer system, and the other the associated MG1.6.
I am not a great believer in breakin, and never performed the kind of listening (the same recording over and over again) needed to detect an effect. If they improve with use, hey...that's great. My cables are also nothing special. The sunwoofers and the woofer of the (2-way) MG1.6 are wired with generic #12 wire, with no terminations on either end. Bare wire, clampred into the binding post, which IMHO is the best way to do it unless you need to disconnect and reconnect the speakers frequently. The MG1.6 high end is biwired with deliberately small #24 wire. This gives me a 1 ohm resistance in the wire so that I don't need to use any tweeter padding resistor in the crossover. The MG 1.6 crossover is, by the way, modified with a large aircore inductor and fancy capacitors.
Of course the modification shops claim that this amp can be significantly improved, for a price. Since you have two, and really only need one, why not send one off for a mod, and see what difference it really makes. If you do go to biamp, you could use the modified amp for the high end, and stick with the stock amp for the lows.