6 1/2" Speakers in hatch/doors?

I am getting ready to replace the factory 5 1/4 in speakers in my '91 Larado(yea, I know, it's about time!). I am just wondering if 6 1/2's can be put into the doors and/or the rear hatch. I know the hatch is all fiberglass and just want to make sure there's enough material out and support the extra size and weight of the larger (even if only a little) speaker. The Jeep is my daily driver as well as my trail rig so the speakers in the back get abused by luggage and other stuff on the trail. Thanks for any advise.

I've done it in the doors but not the hatch. It does require you to drill some new holes though to mount the speakers, measure twice, cut once, its tough to get right on.

Instead of cutting you could try a 6" speaker like the JL Audio TR600's or the VR600's if you're going to use an external amp.