In the spirit of the "keys support" filter, it would be very handy to have one for "2x bass support". Right now, you kind of have to know which songs are supported, as there's no flag.
One way I see to accomplish this is to have a field included in the dta so that the game reads it when building the cache.
Maybe this could add in with a potential Nautilus update to find note 95 and add the value in dta. But in the meantime, it would be cool to have this for all the legacy songs info that is built into rb3dx.