In theory the Model 8 should have more bass control of the 801 for the 400 watts into 4 ohms instead of the Plinius 220 watts.
Uh, you really think the speakers would be underpowered with 220Wpc @4 Ohms? You should also know the 103 delivers 345Wpc into 2 Ohms. If you think that’s not sufficient to control the 801’s woofers I think you’re kidding yourself. At this level of power, just go by which amp gives you the sound characteristics you’re looking for. Just my $0.02 FWIW.