Warbleed

I own the XS-65s. I like them a lot, although I did replace the mids with the AA 6.5s because they have a lot more throw. Good set overall.

I love passives. Be excessive. 2x Vd is the rule of thumb, as a MINIMUM. As Nick said, the end result of you underestimating how much PR displacement you need is you end up with an expensive new bowl/hat. The TC passives aren't terrible, but they are rather heavily overpriced. Also, overexcurting metal cone = bad. You don't want to do that. Wood pulp/paper flexes, metal bends, and stays bent.

A dog farting into a megaphone sounds better than an L7 in a ported box. That is an absolutely awful awful awful enclosure choice for that woofer. Seal it or don't bother, and make it a big sealed box. Try this to test SQ. Cover up the port. I bet it sounds 100x better.

Looks like some pretty serious user error.

There is no such thing as underpowering, only overpowering. Just don't be stupid and you'll be just fine. No one has ever blown a speaker from too little power. Lots of dirty clipped power from an amp being raped and impeding the cooling motion of the moving assembly, yes. Killed by too little power, no.

Nice looking woofer, Nick. You're still a basshead though.

Looks nice Mike. It'll be interesting to see how it performs. If beating the piss out of one is needed, I do have a QSX PLX-3402.

I think the XXX's have their niche. They are by no means budget/bargain oriented drivers. They are intended to get the customers who want near W7 linearity/performance, but don't want to dish out that kind of money. They aren't exactly intended for your average teenager who wants to get bass for cheap though, as their price is certainly not low. That being said, their performance to cost isn't bad at all, nor is it the best out there. They are very high performing competent drivers, although I would agree that they have been rather excessively hyped, but you can't really fault RE for that, since they aren't really responsible for them getting hyped up.

It's great that AA is selling off their stock so cheap, but I feel the whole Dan Wiggins' comment deal was blown waaay out of proportion. I think all Dan meant was that all XBL^2 drivers don't perform identically, and not that Adire made XBL^2 drivers are superior to other XBL^2 drivers.

Yea, parts express has carried Morel for years. Morel makes very good gear, personally I think their mids are absurdly overpriced for how little displacement they offer, but their tweets are awesome.

Looks like some pretty solid drivers to base an active system off of. Should turn out well.

2cf is far more than you are going to need for a vented 10, and honestly that would work pretty well for most vented 12s as well. I run a single TC7 10 in 0.7cf sealed off of 225w, and it's more than capable of matching and exceeding my front stage. Personally I'd just run a single good 12 in a sealed box. A 10 won't offer "better SQ" if that is what you were looking for, and a sealed 12 can offer as much output as the ported 10 as well as vastly superior sub 30Hz output, and use about the same size box as the vented 10 would. With the budget that you have available, I'd say the Avalanche 12 is a good option, as well as the RL-p 12. If you want a really good deal, I'd also consider the Dayton Titanic 12 MKIII as well as the Soundstream Exact 12. Now obviously those are far below your budget, but I think that they offer an exceptional bargain and performance, without the usual pricetag associated with it. The Avalanche and the Rl-p are both capable of more output, but the Vd/$ is lower.

Honestly, virtually any single sub setup with even a few hundred watts can easily overpower the front stage and cause hearing damage. Some people like having the bass be 20dB+ louder than the front stage, but these people also wouldn't know what SQ was if it slapped them in the face with a 2x4. I'd recommend just going with a single RL-p 12 or 15. For maximum accuracy, I'd nearly always recommend sticking with a sealed box. As denim said, 500-600w is more than sufficient for musical purposes for either woofer. I'd just disagree with the vented suggestion and just recommend a sealed box, as that's still more than capable of providing sufficient SPL levels for what you seem to want, and will have far superior sub 30Hz frequency response vs a vented enclosure, as well as occupying far less real estate in your trunk.