[Suhiir]

The M1IP was an upgraded M1 but not an M1A1 with a 105mm.
M1IP had increased turret armor, strengthened rear hull, new final drives, new wind sensor, improved turret ammo doors, and incorporated the new bustle racks as a production item.

The M1A1, naturally received the 120mm, had increased and different turret armor from the M1IP, new CWS controls, NBC overpressure system, All main gun ammunition separated from the crew, new improved final drives (3rd variation), a new wind sensor (3rd variation), new MRS collimator, fitted to receive NBC warning system and roof built to receive the commanders independent thermal viewer (CITV).

M1A1SA (AIM v.1/2): fully loaded: 63100 kg turret: 24400 kg hull: 38700 kg
M1A2SEP (v.1/2): fully loaded: 63100 kg turret: 24400 kg hull: 38700 kg
So it seems that this variants got similiar armor.
U.S.M.C. M1A1(HC)FEP, similiar to M1A1SA.
The M1A1HA, sometimes refered to as M1A1DU or M1A1 Heavy, were sent to ODS with DU armor.

GENERAL DYNAMICS GREEK TANK DOES NOT CONTAIN DEPLETED URANIUM (January 18, 2001) General Dynamics' offer of main battle tanks, ammunition, and the lease of US Army M1A1 tanks being reviewed by the Hellenic Ministry of National Defense does not contain any depleted uranium (DU). General Dynamics Corporation did not offer the Hellenic Ministry of National Defense any weapons containing DU, and did not use DU munitions in any of the tests. Sales of main battle tanks and ammunition to US Allies - Egypt, Saudi Arabia and Kuwait - have never contained depleted uranium. While the US Army uses depleted uranium munitions and armor, however, it has never offered it for export with its main battle tanks.