After doing some research and reading several related threads, I decided to ditch the OEM JBL sub and replace it with a JL8W3. My overall concern was would the sub fit behind the factory JBL panel. I recently blew a dash speaker and already had an Alpine headunit so I decided to replace all the speakers and use a previous 5 channel amp and Audio EQS EQ to do the upgrade. The end result was much much better than the OEM JBL system. For the JL sub, it is pretty much unreal.
I have a background in car audio and have been around the sub block a time our two. My last 4Runner had a JL10W3. The JL8W3 in the OEM enclosure can carry every bit of sound my 10W3 could. It is not just a night and day change, it is a stratosphere above what the OEM sub was. If your vehicle can accommodate the $180 OEM enclosure and you want near over the top sound it is well worth the upgrade. Everything tucked behind the factory panel with room to spare. The 8W3 is powered by an Alpine PDR-V75 5 channel amp with the 5th channel rated at 250 going to the sub. I added the optional sub volume control knob to the center console which is a must if you are adding this sub.