they will just not hold up to the kind of pounding that bassheads want.
Not JL's market audience.
If all you want to do is drive around with the bass blaring, pissing people off with your "music", and generally giving the car audio aftermarket a bad rep then JL subs are not for you. Don't buy them. Avoid them like the plague. You can spend less money and get the noise you want. If you think that you need 1kw on a sub to make up for your lacking elsewhere, then JL is not for you. If on the other hand, you listen to MUSIC at a reasonable level and want accurate reproduction of the bottom octaves, then look at JL.
I've not been on this forum long but I've grown sick of every response to somone's question being "those subs ****, these get louder." Whoopty frickin' do. There is so much more to a quality sub than getting loud and unfortunately that point is lost on too many people. SPL competition is one thing and I respect the guys that do it and do it well. Punk kids who don't think that they get enough attention and so want to make everyone look at them because they are just the "coolest" with all their racket are another story. They give the industry/hobby/sport a bad name, just like street racers give the performance aftermarket a bad name. Any sub can be blown. Especially by these idiots cause they think that the gain adjustment is a volume control. That think that bass boost will somehow allow their system to defy physics and produce more power than it is capable of producing. They run their amps way beyond clipping and, since they bought the biggest inexpensive amp they could, it does not react well to being clipped. Subs die horribly. Blame the subs. Its their fault they can't handle 1kW of DC. Ported boxes are louder. Tuned to 45 Hz is louder still (Sounds like @$$ with music but loud is all that matters, right?). These subs are rated for 400W. I only have 300W so I'm safe. Hey this CD has really low bass, like 15Hz. Hey why are my subs destroyed? They ****.
JL has won a ton of awards and competitiors using their products have won competitions at every level. SQ competitions. JL subs are not rated to handle a whole lot of power. The thing is they are efficient drivers and don't need a lot of power to do their job: play low frequency musical material accurately. There are many subs out there that have better excursion capabilities than most all of JL's line of subs and make better drivers in an SPL application, but there are not many drivers that will deliver the detailed sub-bass at moderate levels and with low power that the JLs can.
I case you can't see through my sarcasm, my point is that JL subs are made for a certain segment of the market, and that segment is not the street beaters or bassheads. That segment is those of us that like music and want it accurately reproduced with correct tonal balance and don't want to have to replace every component in the charging system in our car to power the small nuclear reactor that is running our stereo system. Saying that they **** because they don't soak up a ton of power and get really loud is like saying that Ali wasn't a great athlete because he couldn't play hockey.