I play with White 1.d4 2.c4 3.Nc3 against many openings for Black including QGD, KID, Grunfeld, NimzoIndian defense, and Averbach variation in the Modern defense, etc. Recently, I have been facing this line in the Modern defense
[FEN ""] 1.d4 g6 2.c4 Bg7 3.Nc3 c5 4.d5 Bxc3 5.bxc3 f5!
I tried to look at the database and couldn't find something that I can understand to play against this line. I also tried to look at 4.Nf3 and I didn't like what I saw. Let me know what line do you prefer to play against such a line and the ideas behind it please.
Edit: I found one line that goes like
[FEN ""] 1.d4 g6 2.c4 Bg7 3.Nc3 c5 4.d5 Bxc3 5.bxc3 f5 6.e4! fxe4 7.f3! e5 8.Nh3!
It's a crazy line and I believe that Black would be much more prepared than White on average in these positions.