FI Audio SSD 12 or 15"
http://www.ficaraudio.com/product/ssd-series-ssd12/
Sundown Audio U series 12 or 15
https://www.sundownaudio.com/index.php/products/subwoofers-2/item/u-series
SA two 8" or 10", single 12 or 15
https://www.sundownaudio.com/index.php/subwoofers/sa-series
Last option would be a pair or Sundown Shallow mount but these could be same as the W6 or possibly a downgrade as I have never heard those JL's. Surprisingly, these hit pretty hard in a ported box. I had one and I was very happy for the 2 years I ran it. Then got the bug to upgrade.
I have a pair of SA15's and they hit pretty hard. Over all satisfied with the sub. The top links would be my suggestion based on box size and power you are working with. Don't let the rms specs fool you, they go louder than whats posted. So many people on the forum rum Sundown or have had sundown. Its a great "first sub" till you get to the bigger series.
Never owned FI product but I am considering SSD or U Series for my next upgrade.
Not sure if its been mentioned but I would do "the Big 3".
Hope this helps.