Seeking to Upgrade Subwoofer from SVS SB2000

My apologies for my request. I originally said in my post that I wanted to spend $1000.00 in total. The number was $2000.00 for 2 subs.  I am willing to spend $1000.00 per subwoofer and as of now I am interested in the SVS SB-4000, which is on sale for $1299.00 each with a $200.00 discount if you buy two.

Your idea of a pair of SB-4000 is a very good one. As an owner of six SB16Ultras (2 stacks of 3 each) I'd say if you can stretch your budget, the SB16Ultras would be an even better choice and they are on discount now too, since the release of SVS' new 17" flagship sub.

I've used my SVS "six-pack" with Sonus Faber Aidas, Wilson Audio Alexx and now Avantgarde Duo SD G3 and I can guarantee you will not run out of quality, musical bass regardless of your main speaker choices in the future, even with a single pair of SB16Ultras

I am unaware of any other high-end brand of subwoofer at the budget you want to stay within that would compete with SVS.

I use 2 Rel 510s with my Martin Logan 11A Impressions. You might get some used nearer your budget? I have also had great success with diy subs.

You can do a lot better than the subs you have (which are more of a generic boom boxes actually).

REL, Golden Ear, B&W, KEF, Martin Logan and many more.

REL would be my recommendation for the gear you have.

used REL Stratus can be had for $400 and is still a great subwoofer. A bit big though..