4x4 engines have a dedicated port that return oil below the oil level that the std bretaher also returns it to, the uprated breather also return oil in the same way to the same place by the smallest port at the bottom (the angleed one) yes the tank is baffles inside, i made 100% sure of what each port did before plumbing it up with using water connected to each one and checking where it came out.. btw, IIRC my breather/seperator is actually a pace one, but i painted to so it would blend in a bit better.