I'm more confused than when he first posed the question. What is "bogging" the car?
They way I've seen it from the drivers seat is,
D in M mode = I've heard this is equivalent to 4th gear in M mode, but in my experiments the car seems to drive similar to when in 3rd in M mode. I'm not completely sure about this arrangement.
3rd in M mode = burning more gas+driving at higher RPM = faster accelaration, quicker speeds, best for racing or accelerating on flat, smooth terrain.
2nd in M mode = Gives more power to push uphill, I'm not sure what is happening under the hood but I believe it gives more push power and less emphasis on speed or acceleration.
1st in M mode = For steep almost vertical downhills. Thats all I know about this arrangement
If you set your car to D in A mode the car will shift between all these modes automatically. However the main difference between A and M modes seem to be Machine (car doing it) VS. Man (you doing it).