A simple (ha!) question on the M113 APC

Both of those are available. The M901 is just a paint scheme that you can do to the Italeri kit or find the Verlinden M901 conversion (I have an old unused one) or convert the Academy M981 kit.

The ADATS is done by Legends https://hlj.com/product/LEGLF1286

This would be a cool build, if it existed as a kit

http://img.bemil.chosun.com/nbrd/files/BEMIL085/upload/2005/08/Moveme3125.jpg

This looks interesting as well

http://www.smallscaleafv.com/inspiration/cache/wayne-bowman/m901-jordanian/m901comp-5_700.jpg

Yup. I like some of the different armament seen on Vietnam 113s. The TC's .50 replaced with a minigun, or a 106mm recoilless rifle was seen mounted near the cargo hatch. The  "zippo" turreted flame tracks. All sorts of weapons were tried.

I like the Vietnam era ACAV versions with the chicken coop around the commander cupola and M60 gun shields in the back. It was interesting to see those kits reappear on M113A3s during OIF.

Not a kit so much as a 'someday' project, the fire and rescue M113s that NASA uses around its launch facilities have always fascinated me.