I,ve never noticed any diff at all between just running between 1-3 in a mode or running between 1-3 m mode also there is a huge lage between gears in a or m when shifted manualy.I have to move the shifter at around 6K inorder to have the trany shift by 6.5K,also the computer wont let you down shift manualy intill the car slows enough for the lower gear (which is to slow to wait), by manuay shifting gears gas milage is worse, and there is no overdrive (which adds alot of power in automatics), and you have a verry good chance Of redlining, which is bad for the engine. just let the auto trany do the work it dose a good job. the only reason you should use the gears manualy is in adverse conditios such as ice,snow,mud,or going down steep hills.
speed and power wise I would win in full auto compared to manualy changing gears guaranteed
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