The recommended 1.4 cf box is on the link I posted above. After TC Sounds sold off the last of their db500's, they removed the page from their site. The wayback machine (archive.org) is a great way to find old information.
Are you wanting a DVD unit for yourself or for kids in the back seat. It is illegal in 99.9% of the country to have a DVD screen in view of the driver while the car is in motion. It's not enforced much or the guys here in Memphis with monitors in their sun visors would get busted all of the time.
And I would think a TV tuner in a car would be useless. It's difficult enough to get the proper antenna to pick up HDTV at a stationary house. I'd hate to have to mount my
40" UHF antenna on the roof of my wife's Lexus. She won't even let me upgrade the factory speakers until the "new" wears off.
-Robert