"For some reason I can't tell a difference between power and comfort. When the switch is set on normal and I floor the gas the power switch lights up. The guy at the transmission shop said the switch is supposed to change the suspension settings too. I personally don't see any changes in anything. Can you really tell a diference or is it just in your head?"
You need to go to a different tranny shop then. That guy is a dumbass.
What the switch does is it changes the shift points of the tranny, but ONLY under part throttle. at full throttle, the tranny ECU automatically engages "power" mode and shifts at the max 'useful' rpm. on my car, it shifts about 5800rpm at WOT.
Let's assume you're doing regular city driving-Under part-throttle situations. with the switch in "normal" mode, the tranny will usually shift around 3000 rpm. (just throwing in a number. I usually give enough gas so that it shifts about 4000. others never see theirs go above 2500).. let's just say 3000 for a nice, round number.
When you flip the switch into "power" mode, the tranny will shift at a higher RPM given that all other conditions are exactly the same. it goes up by about 400rpm. sooo it will end up shifting at 3400 instead of 3000 in "normal" mode.
When you switch to "comfort" mode, the tranny will shift SOONER. about the same difference.. so now the tranny is shifting at ~2600rpm.
It does nothing other than change the shift points. the tranny does not shift harder or crisper, nor does it change any other settings- whether it be engine, tranny, or suspension. it ONLY changes the RPM that the tranny shifts at.
As for the gas mileage thing, you will generally get better mileage when you drive in "power" mode. the reason being is that when you're driving around the city, you're on and off the gas a lot.. start, stop, slow, speed up, etc. if the tranny is in a lower gear (since you're in power mode, it will stay in a lower gear for longer), the car wil have better throttle response and accelerate quicker, simply because you're in a lower gear and the engine has more torque going to the ground. THUS, you won't have to mash the gas pedal to the floor in order to maneuver around the little old lady on your right and the car 100 yards in front of you trying to turn left.