will it sound like crap? or not sound at all? I am considering putting some subwoofers in my trunk, and would like to know if that will be worthwhile, or if I will need to hack my rear deck to peices in order to get sound.

If I remove the trays in the deck, will they go back seamlessly? I dont want to harm the vehicle just to have sound.
Has anyone tried the "bass shakers" that mount under ones seat? Do they work and would they give me a similar sound and feel as regular subs?
Thanks for your help!
Moparmike