Now that the 0.9.7 update is live, Wargaming EU just shared the new and first Premium Tier VIII medium Soviet Т-54 First Prototype overview.

Its final characteristics are as such:

Hitpoints: 1,300 HP
Crew: 4 (Commander/ Radio Operator, Driver, Gunner, Loader)
Weight: 35.5 t
Maximum speed: 44 km/h
Engine: 520 h.p.
Power-to-weight: 14,47 h.p/t
Hull traverse: 42 deg/s
Turret traverse: 40 deg/s
Viewrange: 360 m
Radiorange: 700 m

Hull armor: 120/90/45
Turret armor: 180/120/75

Gun: 100 mm D10T-K
ROF: 7.41 shells/min
Penetration: 175/235/50
Damage: 250/250/330
Accuracy: 0.38
Aiming time: 2.6 sec
Depression: -6/+17

Armor schematics:

Recommended equipment by Wargaming: Rammer, Vertical Stabilizer and Ventilation.

There is some more info ahead on this link like the distinctive features of the vehicle and its tactical role on the battlefield: