My VX had a 12" sub woofer in the back door before I got it. It still had the whole cut with a speaker grill mounted, monster wire, and spray foam in bottom of door. I just got a good plastic door panel for $20, so it's going back to stock.
Vehitrails
Instead Of Cutting Into The Rear Tailgate Door Panel I Installed A Boss Thin Low Profile Enclosed Subwoofer. The Sound Is Fantastic !