I have recently gotten into the DIY thing and have an SVS 20-39 PCi w/the upgraded NSD driver available.
It's in very good condition and it's never been overdriven, never had a single issue with it whatsoever. It is still within it's 3 year warranty period (bought 6/30/05) and the new driver is also under warranty (purchased 5/21/06 w/3 year warranty), which both I believe are transferable. Still have the original packing material, so shipping shouldn't be an issue.
Asking price is $425 plus shipping. For those in the Atlanta area, you can save on shipping costs by picking it up. Can also demo for those who've never heard it, but for those who have, you'll know how good a performer for the price this sub is...
-TD