Remember, not all Stilo's have ESP. It started out being just the 1.8, 2.4 & JTD. I believe around 04 time it became optional on all models.
All Stilos have ASR - some don't have the ASR button, as the Stilo adopted the ABS system from the Alfa 147 (v.8) which deleted this button. Vehicles with ESP, however, retained this button.
I can hear you asking now "How do I know if I have ESP?" Simple. GO into the car, turn the engine on, and press the ASR button. If the lamp on the button lights up, but NO lamps appear on the cluster, then you have ESP. If a lamp does appear, then you don't.