It's just too bad that I don't have the money at this very moment for the awesome deals.. I plan on doing this around mid to late January. I'll have plenty of money then.
sundown sa12 will smash the w3 although imo customer service lacks with sundown but their products are top notch.
Going back a generation, I hated my 10w3v2s and was less than impressed with them in JL Audio's recommended sealed enclosure. The Phoenix Gold RSd 10s that I sold with my 1997 Civic actually sounded better in the same sealed enclosure than the JL Audio subs did. It took me a while to wrap my head around that one because they actually modeled within 1 decibel of each other, yet the Phoenix Gold subs seemed to hit the low end with a tad bit more authority. OTOH, the JL Audio subs hit the useless upper end with much more authority. At the time, I was into drum and bass, and a strong 80 to 120 Hz response was NOT what I was looking for.
I used to swear by old school car audio gear, now I swear at it!
There is a guy on DIYMA who upgraded from JL W3 to a Scanspeak Discovery subwoofer (Peerless XXLS clone, made in Europe). Based on review, it seems like it was a big improvement in SQ. Though, if you look at the price, at $270 the Scanspeak is not exactly in the same price range. It's considered one of the best subwoofers for SQ. Peerless XXLS subs are used in home and car audio and were tests on Klippel.
Here is the link:
Review, ScanSpeak Discovery 30W/4558T 12" Subwoofer - DIYMA Car Audio Forum
If you want to stay in the same price range, maybe try the new Alpine Type R12? Or perhaps a couple of R8 in a ported box? There are some long discussions dedicated to R8s on DIYMA forums. These supposedly are overbuilt and have unusually good SQ for their price. I have been very happy with an Infinity Kappa 120.9w, but I have no idea how they compare to JL W3. I selected this for low qtc in a 1cu ft box, low inductance. This thing sounds tight, clean, and digs deep with good energy and transparency, but not an SPL monster. 500watts RMS is probably tops you can run to it.
Just an fiy, the w3's were never meant for pure SQ.
Silently stalking you through glass....