I drive on "I" mode 99% of the time. I've gotten used to the throttle output of it and its pretty smooth. I have no problem passing cars or accelerating on "I" mode. But the other day, I had a 1/4 tank of gas left and was on my way to fill up. For the hell of it, I switched it to S# and from driving on "I" for so long, the car felt completly different. Felt like it just got a shot of steriods. Throttle is super sensitive also. I wasn't used to all that instant power. It sure felt good driving the Outback.