Confirmed MW3 Perks: Tier 3

Marksman: Identify enemy targets at longer range.

Marksman Pro: Longer hold breath.

Stalker: Move faster while aiming.

Stalker Pro: Delay enemy Claymore explosions.

SitRep: Detect enemy explosives and tactical insertions.

SitRep Pro: Louder enemy footsteps.

Steady Aim: Increased hip fire accuracy.

Steady Aim Pro: Weapon is ready faster after sprinting.

Dead Silence: Footsteps are completely silent. Rumors suggest Pro version prevents fall damage.