Stock car will have knock with the supercharger heating the air on intake. The PCM retards the knock to preserve the engine by changing timing/fuel. Combating knock is necessary to obtain max efficiency/HP when modding because you are pushing things beyond their designed limit/tolerances. Without modding, by keeping all your maintenance up to date, fluids, plugs, wires, etc., should keep things ok. With modding it becomes more critical to monitor and address if it is present, doing as much as possible to lower it.
Without a large investment you can get a Bluetooth OBDII reader on eBay and use an android app called torque to see everything the PCM see's (monitors) and know what's going on. About $30 total.
