Other cosiderations:
M3 Bradley IFV (infantry fighting vehicle) "As with other infantry fighting vehicles, the Bradley is designed to transport infantry while offering at least some armored protection and while
providing covering fire to dismounted troops and suppressing enemy tanks and armored vehicles." is much more similar to a M1A2 Abrams MBT (main battle tank) than a Humvee
If you sustain that "mechanized infantry" is a infantry unit it should be represented by an humvee ("The HMMWV was designed primarily for personnel and light cargo transport behind front lines."
http://en.wikipedia.org/wiki/High_Mobility_Multipurpose_Wheeled_Vehicle#Usage_in_combat) or a APC (armored personnel carrier)
In Civ if you see AntiTank Infantry and SAM Infantry are represented by soldiers on foot but in true life they reach the battlefield in humvee or APC
In true life if you would to attack a M3 Bradley you must use a stinger or a TOW or you need a tank.
at this point 2 possibilities:
1) mech infantry change graphic representation: a humvee with 2 soldiers on foot entrenchd in front of the humvee and a third ssoldier on the humvee using .50 caliber machine gun. And doesn't require Oil.
2) introducing a new unit: "light armored infantry vehicle" a humvee with 2 soldiers on foot entrenchd in front of the humvee and a third ssoldier on the humvee using .50 caliber machine gun. And doesn't require Oil. With a bonus agaist Anti Tank Infantry.
Regarding AntiTank Infantry in Civ: his bonus is only against Tank and Panzer because if you want attack a "modern armor" you must use a gunship, but if you don't have Oil, no gunship. So I propose to give a anti "modern armor" bonus to AntiTank Infantry.