Have a crazy idea!!!

Hey guys i was just wondering on something here cause ive kinda wanted to try it. I have a KLH powered 10" sub that has a built in amp, for an entertainment center, and i was wondering if it was possible to rig it up in my trunk for a day or two just for sh@ts and giggles. (without harming my cdplayer or anything. If so would it be fairly easy??? If so plz tell me how i think i might have an idea cause i have a 12volt power converter i can use to plug it into and all i just need to know how to hook it up to my amp. any input would be great
Thanks guys-

If you already have the 12V DC to 120V AC converter, all you need to do is run some wire that carries a sound signal(maybe disconnect a non-amped speaker and run the wire to your house sub). If the woofer is already amped, I wouldn't hook it up to another amp though, I'm not sure what hooking amps in series would do, but it might ruin one or both of the amps. I would simply connect some speaker wire from the radio. If you have a bass output from the radio that would be the best.