I have not been able to find any online detailed review of this kit.

According to online info the real vehicle has a new gun, new engine, commander's independent sight and like the B3 version the same Sosna gunner's sight and new type of reactive armor.

My questions are
Should the engine deck, the main gun and the ERA be different from that of the B3 versions? From online photos, it doesn't seem noticeably different.

Furthermore, online picturs of later version of the B3M have additional ERA boxes on the back sides of the turret and cage or grill armor at the back of the turret and rear part of the side skirts. Does the Trumpeter kit have these later features?

Hope this will help.
http://www.1999.co.jp/eng/10471782
And I think Trumpeter has made a mistake, it is a T-72B3 kit, not T-72B3M.

Thank you. The site is useful.

https://www.cybermodeler.com/special/kits/kit_armor_scale.shtml

Over on Cyber Modeler, they mention that Trumpeter plans to release a T-72B3 M2016 Kit # 9561 I wonder if this is the "late" version of the T-72B3M ? The version with the slat armour in the back of the skirts and the turret and the different ERA ?

I'm afraid that you confused those 2 variants and mixed up the name from Internet....
T-72B3M is the version that Russian used during Tank Biathlon during past 3 years. It has individual Commander sight on top of the Turret which is very identical.
As for the version you mentioned with additional armor? That is called T-72B3 Mod.2016 with enhanced protection(from Russian official site). The basic model of it is still a T-72B3, not a B3M...
And of course.. Trumpeter also have this version of T-72B3 incoming for next year.
Cheers

Thank you for the correction. Websites mention the T-72B3M have the Relikt ERA but visually it seems no different than Kontakt 5 so is the difference inside the ERA panels? Or should the different ERA have different shapes or arrangements?

Forget the website which identify T-72B3 M.2016 as T-72B3M, the relikt ERA are just the side ERA pack of the turret.

Thanks for the correction. It seems Google images pulls all kinds of miscaptioned pictures.

Funny, but even Russian MOD website once called so called "T-72B3 model 2016" T-72B3M
https://function.mil.ru/news_page/country/more.htm?id=12140417@egNews

Some walkarounds

So called T-72B3M (tank biathlon variant)
http://www.vitalykuzmin.net/Military/Tank-Biathlon-2014/i-X6cwx3z

So called T-72B3 model 2016
http://www.vitalykuzmin.net/Military/T-72B3-mod-2016-walkaround/
https://www.dishmodels.ru/wshow.htm?p=3598
https://www.dishmodels.ru/wshow.htm?p=3596

Thanks for the links.