knock sensors are fairly useless in their operation, they don't tend to do anything in the high rev range as its so noisy its hard to determine any knocking. thats when you most need them! are you sure its pinging? coz a factory turbocharged motor running basically a standard setup should not have a problem, especially if running 97 ron fuel (which i've never heard of). optimax, BP ultimate and i think mobil synergy are 98 RON, all other premium unleaded i believe is 95.