You don't really avoid the D-pawn specials with 1...c5 since White can still play 2.c3 or 2.e3, or even 2.Nf3 cxd4 3.Nd4 followed by c4, and you have various other lines to contend with. The 1...Nf6 move order is probably better if you are a Benko player.

Thank you! does that mean that this move order kind of forces white to play the main line? if thats the case then i would play this as black also because i like to play Benko gambit as black and get rid of all those annoying side lines.

It depends entirely on what you would normally play against 1...Nf6 and 2...c5.

- 3.c4 allows the Benko, Benoni and Czech Benoni.
- 3.Nf3 is a standard Anti-Indian line.
- 3.Bg5 transposes to the Trompowsky line 1.d4 Nf6 2.Bg5 c5 3.d5 (though with the 1...c5 move order White loses the option of playing the main line 3.Bxf6)
- 3.Nc3 might be the attempt to punish Black's move order, often leading to a Schmid Benoni (with Nc3, Nf3 and no pawn on c4). But it's far from clear that the standard verdict of += really holds.