mount them however they fit best, but you will probably get better sound when they are backwards. i have these same subs and it depends on how big the box is and what your putting them into , ive had them in 3 different cars, first in back of a 89 s 10 with a small box, sounded ok, then i put them in the back of a 98 s10 turned inside out in a custom box, i think each speaker had around 1 1/2 cubic foot of room with the speakers pointed up, and they sounded amazing , they basicly just used the truck as a speaker box, now i have them in a 95 prelude trunk, and with such a small truck i had to give each speaker less than a cubic foot of box and they sound horrable,