Subwoofer for classical music listener

My floorstanders are competent for general listening of all genres of music, classical included without a sub.

Once hearing "Tocatta and Fugue in D minor" and the 2nd movement of Ludwig V's 9th with a sub, no turning back.

Dual Rel B3's(way outdated) deliver the goods. The new models
can be found used/demo for decent prices here on Agon.

The others-JL,SVS,Rythmic all good. Just do the homework with research.

Thanks for the responses.
I have a 25'x23' foot room, a much modified vintage system with great impact  which, to me, is perfectly balanced for classical except for ultra low bass (e.g. organ).
 System:
Modified Dalquist DQ 20 speakers, modified Nuforce amps, modified vintage CJ preamp, Theta DAC, Oppo BluRay player used as transport, Rega RP3 turntable, Grado Sonata cartridge.
I would like to spend around $1000, more or less (preferably less.)

A pair of Vandersteen 2wq's would be my recommendation, though a pair of 2w's would probably be as good.
B

Gallo TR3 is 799$ new, used ones don’t show up on here(a good thing). One sub is all that’s needed to play the odd organ piece and relieve mains from
burdens below say 80Hz which brings more clarity which is always needed .
I’ve heard Vandy subs but IMO Gallo beats them.
If your Oppo is less than a 105 a Cambridge CXC transport(449$) might do more for system than sub .
Might do more if it is a 105 .

Some say two subs evens out bass in room. I've found one is enough IF you get the placement right .