There is a story that is encountered in memoirs about Soviet tank building, describing how Stalin climbed up on the SU-152 during an inspection of new vehicles in the fall of 1943, and personally ordered that an additional ventilation fan be installed in the roof of a SU-152 after speaking to the vehicle's driver. The story may be apocryphal, but such an order was issued soon after the demonstration either way.
"To the Senior Military Representative of the GBTU USA, Engineer-Lieutenant-Colonel comrade Markin
I report to you that, as of September 23rd, 1943, each SU-152 SPG produced must have extraction fans installed.
The factory will receive orders from the People's Commissar of Tank Production in the near future.
Chief of the GBTU Self Propelled Artillery Directorate, Almoz
Chief of the 1st Department of the GBTU USA, Engineer-Lieutenant-Colonel Demyanko"