I ran the modpack you linked and didn't notice any additional UI messages or log output.
Furthermore I ran the installer in a Windows 7 virtual machine (using VirtualBox) to check if I get the same exit codes as when using Lutris with the chosen components.
Result: I don't get any exit code 4.
Btw. - it would be really helpful if your installer would have a component selection export/import as I solved that by exporting/importing the registry branch which contains this selection (see below).
HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\Aslains_WoT_Modpack_Installer_is1
Then I did a directory comparison between the Windows 7 vm mod installation and the one in Lutris of the following directories (two comparisons):
Games/World_of_Tanks_EU/mods
Games/World_of_Tanks_EU/res_mods
Result: Identical.
I tried to to reproduce the exit code 4 by extracting your installer with innounp and running one of the batch scripts manually using wineconsole.
Result: Script executed successfully without any errors (contained two sed commands).
To me it seems that the start/stop handling for processes and/or exit code handling within the installer may have some issue - at least when run within Lutris/Wine. I tried to get some more debugging info from Lutris, but when enabling full tracing, the slowdown is so massive that the installer didn't even startup in a reasonable time. Even when I run the installer in the Windows 7 vm (which acts fast) I would be able take screenshots from the UI while it builds up.
Currently it's ok for me as the installation result is ok, but you may want to have a look at the batch script handling within your installer and the performance.
Thanks for your help!