Depends what you like. Drivability and power deliver I would pick stage 2. Stage 3 gets expensive and haven’t heard much about. I have stage 2 with roller rockers and think it transforms the motor.
Personally I am curious about shocks like ohlins
My money though would be on lights (jw speakers) if you drive at night.
I did a short shifter and new knob which is good if you enjoy shifting. I might enjoy it too much
