Wasnt this the mortar present in CoH?
I like big guns, but I doubt it will bring a gameplay value to soviets, so it's most likely to turn it down. The 107mm mortar already is borderline in terms of range, firepower and cost, having another even larger super mortar might be over the top. I'd rather go with "real" arty pieces instead like a B-4 or 122mm Firebase etc.