i mounted mine in the stock location. just bent the metal so the basket would fit, and used the stock bolts and everything. you could cut the excess out, but i just bent it under so it wasnt going to interfere with excursion. if you have to change them more than twice then you are not buying a quality speaker, using way too many watts, or have your bass maxed out and it sounds like crap anyway.
yelloeye, is there even enough room between the top of your 6x9 and the bottom of the deck for full excursion? i would think a spacer would be needed so the surround and woofer wouldn't hit the rear deck when the bass was "hitting". it was like that on my cavalier and i had to make a half inch spacer, but i wasn't going to mess around with that this time.