700's. External mods aren't enough to transfer the air they can generate. There was a post from Greg (SZ) explaining everything. I have all the breather mods and 530's. I made 424 Wheel HP in 103 deg F. (SZ tune) I was told sport 700's added alone (no head work) would probably get me near 500 wheel HP. With head work 700's and still using my 615 injectors I would get near 600. The limiting factor then would be my injectors. If I had to do it all over again I would go with the 700's, 740 injectors and head work, especially now that their price has come down.