My wife says the same when she looks at the stack(s) of unbuilt models I have too.
For a USMC M1A1HC, here are the additions or changes to make to a standard (Army) M1A1.
Change out the smoke launchers to the USMC 8-shot, double-stacked type.
APU Power Junction box. New electrical conduit is the angle-iron piece running along the left side of the blow-out panel.


EPLRS antenna mount, minus antenna, capped post to the side of regular antenna. Also shows new, thinner steel antennas for radios too.


Power connection box next to the man-hole cover. There are two screw caps to connect to located on the front of the connector, toward the front of the tank.

PLGR antenna is mounted somewhere on the turret roof. Below it is in front of the crosswind sensor. I have also seen it to the front right of the TC’s cupola as well. The location for it varies.


Tank/Infantry Phone on right rear of hull (and rear Slave Cable Receptacle shown on M1A1 AIMs below, not present on most USMC tanks).

Deep fording kit exhaust flange.

Forward MCB (Mine Clearing Blade) power/control box connector box next to driver’s hatch. (only on later USMC M1A1 AIMs)

The box in front of the loader’s hatch is an MCD (Missile Countermeasure Device). It is used to defeat optically and laser guided anti-tank missiles.

Some USMC M1A1HCs are using the old sprocket guards as well. The older T-156 Chevron Block track had an issue with jumping off the sprockets. The newer T-158 Bigfoot track solved the problem. Originally developed for the M1IP the USMC started putting teh rings back on M1A1s that were stationed stateside in the early-mid nineties. It was an easy fix to counter the track losing tension during operation. The USMC tanks that came off of the Maritime Preposition Ships (MPS) in Kuwait for OIF I /II do not have the sprocket rings. The USMC tanks that you see in IRAQ with Retaining Rings are from stateside (1st or 2nd Tank Bn). They are part of the different ocean-going Marine Expeditionary Units (MEU) that have gone to Iraq and participated in the festivities over the past two years. So, specific USMC tanks could be seen with the rings applied. The below pic is a USMC M1A1HC in ops in Iraq.

For the USMC BRE used in OIF.

Eduard makes one, set # 35598. There is also one in the new Academy M1A1 Iraq 2003 kit. It is one of the few good pieces off the new J sprue. It also has a T/I Phone box on the new sprue. The rest of the kit sucks though.
You can take a look at my M1 Variants Article as well for more info and pics.
You can also take a look at my USMC M1A1HC that I did a while ago.
“Angry American”, USMC M1A1HC
Good luck on it.