you forgot to mention the "parking locker" in the center console All Suzuki LJ's and SJ's (Samurai) made for the German and Swiss market was delivered with a parking locker to lock the rear differential when using the handbrake as the handbrake drum is mounted on the drive shaft :)
Regardless of the diameter of the exhaust pipe at the rear of the vehicle. The action of the car travelling through the air causes a vacuum at the back of the vehicle...hence dragging the exhaust fumes into the cab... Placing the exhaust pipe existing the side of the vehicle can somewhat improve this situation.. But never 100%