Hi
I have Tq on steam (version 1.51) and my friend has this game on gog (1.49). My question is it possible to play with each other? Im thinking of buying game on gog just to play with him but i want to read your ideas.

It is possible in principle, I already played with a friend who got TQ on Steam. But then he got an update and GOG did not, so I can't play with him until they will finally update the GOG version. There are some threads in this forum about that problem.

So I recommend that either your friend also gets the version on Steam, or that your friend gives the GOG files to you and you both play with that (as your already bought it, I guess there are no legal/ethical problems in doing that).