When I first got G350's, had Monarchy SE100's that I had biamped with the previous speakers. There was a hole in the crossover area. Tried Manley Snappers but ended up with Plinius SA100, which blended seamlessly. So seamlessly that trying to optimize phase became an effort. Eventually got two and ran them as bridged monoblocks (400 wpc). All were rated at the same wattage but not created equal. Granted, the 350's ribbons are not a tough load but, like Maggies, love power. Because the Plinius is much more sensitive, the gain on the bass amp had to go up considerably.
BTW, The Genesis system is only an active low pass (Tidal does similarly). Got a NHT X2 and used the 12dB/oct active high pass section at 110 Hz and it sounded cleaner in that area with only the slightest loss of transparency in upper frequencies. Not bad for a few hundred bucks.
GAT sold out of the M60 amps that were designed for the 5/6/7 series but they might be found used.
The Genesis' have a laid back soundstage and the ARC tends to be more forward and "bloomy", so it can make a good combination but that's all subjective. The Plinius, like many (not all) solid state, is more laid back. The toe-in of the speakers affects that presentation as well.