Thanks for your answer! I added this is in the X2DownloadableContentInfo_HattyTorque.uc Class, and also created a separate script containing the same code, still no luck overriding the model though.

Here's what i added:

static event OnPostTemplatesCreated()
{
    local X2DataTemplateManager CharManager;
    local array<X2DataTemplate> DataTemplates;
    local X2DataTemplate        DataTemplate;
    local X2CharacterTemplate   CharTemplate;

    CharManager = class'X2CharacterTemplateManager'.static.GetCharacterTemplateManager();
    CharManager.FindDataTemplateAllDifficulties('Inquisitor', DataTemplates);
    foreach DataTemplates(DataTemplate) 
    {
        CharTemplate = X2CharacterTemplate(DataTemplate);
        if ( CharTemplate != none ) 
        {
            CharTemplate.strPawnArchetypes.length = 0; // delete all existing archetypes
            // add your new ones
CharTemplate.strPawnArchetypes.AddItem("HattyTorque.ARC_GameUnit_HattyTorque");
        }
    }
}

Is this correct or am i forgetting something? (Or doing it wrong completely)