shift at 7600rpm when racing will take you to the redline (7800rpm) in ur 2003 auto GTS (i have the same car) 6000-7000 is too low considering you are racing.
shift at 2500rpm when normal driving.
i played the sportshift after i get the car and breaked it in...and it bored me. it's better to match the rpm using the accelerator in auto GTSs...lift the accelerator slightly, the car will shift to the next gear.
stepping the accelerator will give you 1-2 gears drop consider the rpm and speed (from 4th to 2nd..or if you are in 3rd, it will drop to 2nd.)
beware of that 1 gear in auto get you to around 70km/h redline(7800 rpm)
2nd gear at around 120-125km/h redline
3rd gear at around 195-200km/h redline
4th gear...i dont know, my car stops goin at 200km/h 4th grear 5500rpm..might be the engine couldnt go anymore or the speed in governed.
the sportshift will warn & stop you from dropping gear if ur speed is too high for the gear you are dropping. it will make beep sounds.