The factory plastic baffle isn't difficult to replace with a custom made one at all. It's attached to the door with only four rivets. It would be easy enough with a few nuts and bolts to reattach the factory baffle and keep the good custom made one if a person were to change trucks too. Now I made mine knowing that I would be installing some fairly decent woofers and running some fairly good power to them. That prompted me to overbuild mine compared to what most people would need to do. I also built mine to protrude slightly through the door card (plastic door panel) to improve response and imaging. Again not something anyone would HAVE to do so keep those things in mind when looking at these pictures.
Just FYI this is a 6.75" Polk RSD component set mounted to the plastic baffle.
Here's the baffle by itself.
If you notice the shape of the plastic in the picture of the factory baffle above you can see how I simply traced the outline of the factory baffle onto the wood in the picture below.
I used a router with a circle jig attachment to cut out the rings that make up the rest of the baffle. A jigsaw will work fine.
I used fiberglass resin and rubberized undercoating to seal the wood on my baffles. It must have worked pretty good as I actually (and very unfortunately) submerged this truck in several feet of water filling the inside of the truck to the bottom of the seats and never saw any swelling in the wood (MDF) I used to make the baffles. Even without any intentions on submerging them it's a good idea to seal them so that any moisture they may encounter (Rain, Humidity, etc.) does not affect them.
And finally I mounted them to the door with 3/8" bolts. Again, overkill, but I wanted to be sure that they couldn't have been more solidly mounted.
Hope this helps.