If you prefer playing an anti-vehicle role, the better choice for a suit may be the Flak Armor certification. The Flak Armor certification reduces the amount of damage taken from explosives. Most vehicles and aircraft will be using explosive ammo and therefore in the anti-vehicle role this suit will be more important.
You will also want to get the Anti-Vehicle Weapon certification that allows the MAX to equip an anti-vehicle weapon on both or either arm. Those certifications are the Comet VM2 for Vanu Sovereignty, the MX3 Pounder HEG for Terran Republic, and the NCM2 Falcon L-Arm for New Conglomerate. This will maximize your damage for a anti-vehicle situation, but will lessen your ability to function efficiently in other roles. In addition to this cert, I would take the Laser Sight cert and attach it to the rail of the weapon to increase accuracy when firing from the hip.