trunk rattle

I just bought a 99 civic sedan. I was wondeing if anyone has had problems with trunk rattle from subwoofers. I have 2 JL Audio 12W3's powered by a Phoenix Gold XS2500 amp. The amp can easily overpower the subs. Im taking them out of my old car and I cant decide if I want to sell them or put em in my civic. I just want to know what you guys think before I bust my ass installing all the equipment just to have the trunk sounding like crap from the outside.
Thanks

I used to have a 2000 civic sedan, the only problem I had was the liscense plate, mainly because Indiana ones are so thin that you can twist them while tightening the bolts. To fix this, i just stuck some duct tape under the plate, and no more rattle.