Okay, we've pretty much have the same amps and speakers. I'm using the Maraschino 48V DTMs, so we're pretty much on the same page.
A couple of thoughts...
First, if you don't mind my asking, what speakers were you using prior to the M3ts? Open baffle bass is quite unlike "boxed" bass. Unlike boxed speakers which generate "bass in a box", open baffles generate bass in the room without the help handicap of a box. To the discriminating ear, hertz for hertz the quality and character of this bass is not merely different, but arguably superior to bass made in a box...
Second, fresh out the box, these speakers really benefit from being hit hard with a lot of power combined with bass heavy music for a few hundred hours. Some people pussyfoot around this issue thinking they can break them in at moderate volumes with any kind of music over time. That's not gonna happen; those two big 15" drivers need a long hard rigorous work out before the bass truly forms. When it does, the before and after difference is night and day, with the right amp the bass impact is nothing short of stunning. So the question is, are your speakers really broken in?
Third, your Class D amp is far more qualified to deal with the Spatial load than any tube amp on the planet, especially when it comes to bottom end impact! Some M3ts owners are thrilled with the sound of their SET amp, but when they switch to Class D they are totally thunderstruck at how much better their speakers sound. Your Cherry amp is very special in that regard. There are some other SS designs that will give you a lot of bottom end grunt, but they won't have the neutrality and finesse in the midrange and upper end.