Yeah, terrafirmacraft is awsome and would fit perfectly as early game for gregtech, but as I heard its incompatible and installing both will crash the game (something related to GT ores).
I have a suggestion about a diffrent mod: Glen's Gasses. Gregtech could add suport for it and use coal dust (or a new type of gas, just coal dust have the best properties) as pollution. If mufflers will output coal dust, no chimney = house full of smoke. Also machine that dont have space to put more gas should stop work untill space exists