I was always curious to know why exactly on GRB these two are always at different BRs, even if it just a step forward (talking about the 105)
In-game they are both pretty much the same, and let’s start with the things they share:
Same Gun, Ammo, Gun Handling, Elevation and Depression, 1st gen TVD, even the chassis so the engine power and transmission are also the same. Funny enough the reward multiplier is very VERY similar with the only difference being the talisman x2 bonus
The Differences however are rather small but at the same time big
The 105 has smoke grenade launchers, a taller turret which leaves crew members more exposed and a coaxial machine gun. On the other hand the MTTD has a 6.7s auto-loader so you get always a faster reload, tho the 105 can get this reload tho with aced crew, at least as long the loader is alive which takes us back to the already mentioned biggest of the differences.
The Turret: this is by far the main factor that in my opinion is a game-changer in terms of survivability, on a hull down, the 105 needs to expose itself a lot to shot, in that particular case if it receives a shot the chances of surviving that is moderately low and even if it does you will only have left 1 out of 3 crew members in the turret so now the reload and repair times are much slower, while the MTTD when it peeks it just exposes the gun, if you catch a shot you may get only a damaged breech or cannon and that’s pretty much it, less damage to the crew and always a reload at full capacity.
To summarize it, they do have small but those are not big enough to be apart so they should be in the same BR or in the worst case scenario they should change places, the 105 at 9.7 and the MTTD at 10.0 because the better survivability and auto-loader is certainly a good trade for the smoke grenades and a machine gun or as i call it “useful team pointer”.