Have multiple deployed Sunderers

You can't use the main entrance on the ground, but there are two other ways to enter. The first option is to use an aircraft and land at the pads of the base (preferably with a Galaxy and some friends). There is a small entrance which can be passed by infantery that doesn't have any shields.

Or you can use one of the teleporters found at the small sattelite bases. They look similar to a spawning tube and are often found in a dedicated building. You must capture the point near them to make it accessible to your faction.

This is not a complete answer; however, I have managed to dig up solid information about the tanks here. I still have very little information regarding MAX's, beyond this chart which details their anti-infantry weapons.

To expand on this answer I've found relevant information about tanks. Tanks actually take (default) 50% damage on top and sides, 45% on the front (38% for Vanguards), and 120% to the rear. The armor plating defensive items add onto this, so for example the 5% damage resistance on frontal plating reduces damage to 40% (roughly twice as good as it says on the box). In all cases this results in an increase to the hits-to-kill of one (or two for prowlers, more for Lightning 75mm gun)