Sub suggestions please


I just got a pair of JBL L100 Classics (I have seen that they are controversial here, but I love the look, and am impressed with the sound...I'm a happy camper).  They are connected to the Cambridge CXA61, and I run a Technics SL1600 with a Grado Prestige Green3 cart, and a Cambridge Alva Duo preamp, and Cambridge CD transport (CXC V2).  My sub is a Klipsch Reference Series 12", which I like, but it doesn't aesthetically work with the JBLs.   I'm considering the REL Classic 98, Sonus Faber Gravis II, or the SVS SB-3000 (I was told I could get it in a walnut veneer, but haven't actually seen that.  Walnut is important in this case).  Any seconds on one of those options?  Any alternates I should consider at $1,500 or less (I am perfectly satisfied with pre-owned)? 

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I know the general recommendation is two subs are better, but that wasn't my experience. I started with a single SB1000 and liked it so much, I bought a second. I spent weeks trying to integrate the two, trying different locations and numerous DSP adjustments. I finally concluded I liked the sound of a single one better. I returned the two SB1000s and got an SB2000. It not only sounds better, measurements show a nice flat response below 80hz. 

I cannot figure out how to respond to particular people on this forum, lol -- but I appreciate everyone's suggestions - you've given me a lot to research!  Thank you!