Memphis 1000D with JL 10W7

you can still use this set up, not recomended though, you will not be able to get the power out of that amp you want. I would suggest ditching that w7 anyway. Look at some of the memphis subs they sound great,or Fosgate, There are some subs out there that will sound better than that w7, and who wants to deal with the hasel of the odd ohms on these subs.

Whoa... I completely disagree with wheeler...  

There's nothing wrong with that w7...  3-ohms isn't a hassle either.  Just connect it straight up... positive to positive, negative to negative.  The 400-500watts you'll get is more than enough to drive a subwoofer.  Your girlfriend gave you some really nice stuff (expensive - she must be hunting for the ring soon ;-)!  There are actually few subs out there that sound better than the w7. 

You don't need to get full power out of the amplifier to get really loud.  There'd only be a 3db max SPL difference between 500w and 1000w.  This is tiny to the human ear... 99% of the time you'll never know the difference.  Don't worry about not running 1000w unless you're going to compete in SPL competitions.

Enjoy it, you have some nice stuff there.  Two forum pros Steven, from Adire!, and forbidden, who owns two stores, think the w7 is one of the best subs on the market.  https://www.the12volt.com/installbay/forum_posts.asp?tid=31055&get=last   I happen to agree.

keep your amp, give your girl your sub, take hers...merry xmas

but seriously, no matter how you do it, that will sound good, just make sure the enclosure is done right

What do you think about the enclosure? Right now, the box is about 38Wx 12.5Hx 12D(at the top) and 15D(at the bottom)... (so it will be a wedge) if my calc. is right it will be about 2.96 ft3... (no I am not that bad with a measuring tape... it is going to fit perfectly in the back of her trunk) then I will add dividers to make it about 1.25 ft3, does that sound good to everyone? or not? any ideas?