Question about subs

A friend of mine gave me an Alpine sub with an RMS of 1400W or so. Thinks its 2500-2800 peak? If I just hook up a 1000W amp will it do what its supposed to or will I break things or will it say FU I wont do anything? And to make it more complicated I have 2 figured 1 for XJ 1 for Civic.

You would be fine with the 1000w amp on it. I'm assuming it is a class D. You'll find that pushing a 1000w in an enclosure like an XJ is going to be plenty.