when you build your box, make it a flushmount baffle. that is - two boards deep, and the sub is mounted to the first board with the second board around it.
then, attach your box to the location it will sit from the INSIDE (bolts\screws\whatever)
then, mount your sub.
heres the cool part. make ANOTHER baffle, but cut the inner diamater of the sub again, now mount it to the outside of the box with like 20 security screws. if you got the time, do like 20 different kinds.
that sub isnt going anywhere.
as for the amp. you could do the same thing, mount it behind a panel that is secured to the vehicle with security screws (or some other smart way)
so people basically just cant get to the mounting screws //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif