Help finding a subwoofer

I used Rel Storm iii and Stadium iii in the past so I am not used to crossover for the mains and am scared to do so because it will alter the signal to the mains. But I see the logic of Aliviating the amps job and that is no small feat. Having said that I think that no crossover to the mains is simpler and simpler is better. Now, many subs I suppose can xo the MAINS but then I think it would have to be a real expensive sub to do a really good job at that.

I correct myself, if some SVS models have high level inputs then that is a serious weight against the 3000 micro, which is TOO bad because of the relative advantage of the micro 3000 transportability. See? I wouldn’t mind a smaller sub that fits better in more places and can be shipped in a smaller package.

An active crossover is there is to solve an issue, but you do not yet know if you have that issue or if you even care. REL subs are actually fairly limited in features.  I wish I could easily show pics of my best REL vs best JL Audio waterfall graphs.   Better to be lucky than good, though ;)

I thought that EVERY sub with hi level input and dsp could be used with both working at the same time, Soix!

Thinking of budget I would forego xo to the Mains. And thinking about the high level input the question arise if the the worse tube amp bass performance relative to solid state is due to interaction with speakers is it then less worse going into the subwoofer. If tubes mean bad bass then I would also have to forego high level input .