Olivier Oh ho... I want to see that.

Grease Monkey T-64U is one of 2 variants of the modernization program in 1990s, while "Bulat" is the most recent modernization from 2004. The other one is (I think) T-64BM. The one I have is T-64BM Bulat. So that seems to be the latest version of the BM. BTW, it seems the Bulat did not well in the recent Ukrainian conflict, they send them back into storage and start using their T-64B agian, so it seems. I think the Bulat is too heavy for the 5TDFM engine with 850hp. The top speed is much lower than all other modern tanks. There is an 1000hp 6TDF, but that was an option and I don't believe the operational Bulat's had that powerpackage. But that said, I read conflicting stories on the internet...

Ingo F T-64U was an prototype of the T-64BM Bulat and was first shown in 1999 during the Independence Day of Ukraine. As far as i know only two prototypes were build.
T-64BM and T-64BM Bulat are two different tanks. The T-64BM was an soviet modification of the T-64B with an 1000l engine in the early 1980s. Bulat is an modification of the ukrainian T-64B/BW tanks.
Only my two cents here. Hope you dont mind.

Scott Dutton Always happy to learn, externally much difference? May need to convince myself I need the Miniarm turret, I love their quality stuff

Ingo F Unfortunately there is not much information about the T-64U.
Here a little summary of the information i could dig out:
In 1999 there were three variants for the modification of the ukrainian T-64B/BV and T-64B-1/BV-1 tanks.
The prototypes were called T-64U.
A total of nine modified T-64 tanks were sent to the Independence Day parade:
Six T-64BV-1 with a mockup reactive armor. (1st variant)
Two T-64U (Object 447AM1) with reactive armor, modified gun, reloading and aim systems. New weather sensor. (2nd variant)
One T-64U (Object 447AM2) with reactive armor and modified internal systems, the same that were used on T-80UD (Object 478B) and T-84. (3rd variant)
All in one it looks like the T-64U had a different reactive armor on the glasic plate and the ERA layout on the turret was also different.
You can see the pictures here: https://dic.academic.ru/dic.nsf/enc_tech/4413/%D0%A2
The information on the site is from an russian modeling magazin from year 2000.

Scott Dutton Many thanks

Grease Monkey Good info! Not a lot of info on the internet, about the Bulat and it's predecessors, at least not in English.

Ingo F If you need some information, just ask me. I can try to find and translate it for you.

Grease Monkey Thanks!
I just did a search to check what antenna should go on a T-90K, and in Russian I got a lot more info. (More useful info I should say )

Moritz Fentzahn Looks promising, count me in