Subwoofer placement in 4th order

I'm currently working on a 4th order design for a blowthrough. How important is how the subwoofer is firing? For instance I have one design where the sub is mounted facing the cab with the motor pointed toward the tailgate. The other design the sub is mounted vertically cone facing towards the bed cover motor facing the floor of the bed. If air space and tuning is the same will these designs perform similar?