As an improvement on 1.d4 Nf6 2.c4 e5 3.dxe5 Ne4 4.a3 Nc6 5.Nf3 a5 6.Qc2 d5 7.exd6 Nxd6 8.Nc3 Nxc4 9.Bg5 (Tamburro) in the Fajarowicz variation, I have looked at 8...Be6 9.b3 a4.
Black gets good play for the pawn after 10.Nxa4 Bf5 11.Qd1 Nxc4 12.Qxd8+ Nxd8 13.e4 Be6 14.Bxc4 Bxc4 15.Nb6 cxb6 16.bxc4 Ra4 17.Nd2 Bc5.
A likely continuation is 18.O-O O-O followed by 19...Ne6.