When you push the scramble button and go WOT you should definitely feel a difference. A rolling 3rd or even 4th gear pull should spin the tires.
The stage 3 is plus 3 psi and plus 9 with scramble.
I started on stage 3 also.
Stage 2 is what I run. Plus 6 psi all the time. No power surge under low acceleration.
Your basically running stage 1 without the scramble on.
With stage 2 you can stock on eco mode and plus 6 when on normal mode.
I have a flash pro so I can switch around and the difference is night and day.