2008 Subaru Impreza Owner's Manual - Page 252

7-30 Starting and operating SI-DRIVE (WRX STI) SI-DRIVE (SUBARU Intelligent Drive) works to maximize engine performance, control and efficiency. This system consists of three modes: Intelligent (I), Sport (S), and Sport Sharp (S#). By adjusting the SI-DRIVE selector, the character of the power unit changes. This is ideal for around-town driving and situations that do not require full power output. It provides better control in difficult driving conditions, such as slippery roads or loose surfaces, due to gentler throttle response. & Sport (S) mode For all-around performance driving & Intelligent (I) mode For smooth, efficient performance driving The Sport (S) mode provides the engine power desired by those who want to make the driving experience their own personal adventure. The linear acceleration characteristic of this versatile mode is ideal for normal driving use. When Intelligent (I) mode is selected, a shift-up indicator " " in the tachometer will blink to signal the best time to shift gears for maximum fuel efficiency. The Intelligent (I) mode provides wellbalanced performance with greater fuel efficiency and smooth driveability without stress. Power delivery is moderate during acceleration for maximum fuel efficiency.