The shallow Daytons aren't subs (midbass, sure), but neither are the speakers under your seats - if you look at the Daytons, you'll see how the frame is pretty wide all the way down, and I don't think anyone will be throwing any into an E92.
Spacers are really driver-specific. We don't even use the same spacers for our SWS that we do for our Jehnerts (ID is different), and when we do Morel 9" (which don't fit the E92, due to height limits) it's totally different again.
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