speedoflife

Absolutely untrue. Yes, the dustcaps are very similar, but it is a nice change from the "boob" style cone with small dustcap.
The Havoc's response curve it nothing short of spectacular for a stiff suspension'd subwoofer with high power handling:


The baskets are also nothing alike: the JL has its own unique (but freaking heavy) basket design, while the Havoc has a more traditional 12-spoke design:


The Qts (basically a combination of mechanical and electrical handling of the subwoofer) are nearly identical on both subs, motor strength is not listed for the W7, but the Havoc has a very, very respectable 19.8 Tesla meters. The W7 has a lower resonance at 23.x Htz, and the Havoc's 29.x Htz is a little sad (it's still very good compared to MOST subs) for those of us who like bass we can't hear (just feel), but 95% of your music will be played at 30+ Htz. The power handling and xmax (excursion) of the subs is similar as well (30mm for Havoc and 32mm for the W7 -- more than you'll ever need in both cases). Although the W7 is rated to take 500 more watts RMS, the Havoc is underrated at 1000. My amp puts out 1472 watts at 14.4 volts (my electrical system runs at 14.8-15.2 volts) and the Havoc eats it up no problem (more volts = more wattage output).

However, there is one huge difference in the two subs:
The Havoc literally costs half the W7 and weighs 15 pounds less.

Personally, I think the choice is obvious. Havoc is to F.I. as JL Audio is to HKS. Both EXCELLENT products, but one includes a "royalty" brand fee.

All info on the AA Havoc applies to the Fi Q as well -- they are similarly priced and VERY VERY similar subs (basically the same sub for two different names. (proven by a Fi Q vs AA Havoc test done by me here: Fi Q vs Havoc)

Just let me know if you have any questions regarding subs and/or general car audio!