[rotrex]

Preignition is usually a consequence of knock.
Unless you run extreme compression ratios or get boost spikes that woud result in instant preignition, Diesel comes to mind, it usually starts with "plain" knock. Knock tends to increase local temperatures of chamber components such as spark plug electrodes as the combustion becomes irregular and overall faster. As pressures rise faster than anticipated, chamber temperatures rise rapidly.
The longer it knocks, the hotter bits get until they are so hot they ignite the fuel before spark occurs. You have pre ignition. It is a run-away process. It starts with light knock changing to heavy knock until kaboom, you get preignition. This commonly ends in engine destruction. The entire process can at times take less than a second given enough boost and heat.

If you have a very fast knock control system, it will retard ignition within one revolution preventing the worst. My J&S safeguard worked that way. I have tried it when my priming pump of the old Aquamist race pump failed. I spit huge flames out of the exhaust of my Elise in concerto with big misfires. The J&S pulled 10 deg timing out of all 4 cylinders at once. The TurboXS knocklite also shows single and faint knock events below the audible treshhold. At first I thought it was indicating artifacts, but pulling 2 deg of timing in these spots reproducibly removed the indication.

You can data log the output of the J&S, but commonly there are only a few spots you need to correct under full load.
I have also used it to generate a suitable IAT ignition compensation table for water methanol injection on my engine.
The base settings were mapped at 20-30C IAT with short squirts of power.
The temps up to 50C were evaluated with longer and repeated pulls or during hot weather. The range to about 70C intake air temp, the highest I ever managed, then on track.
Without data logging, you cannot really do this conveniently.
If you push on without active knock controll, you'll eventualy run into trouble.

Modern ECUs have sophisticated knock control.
But for less sophiticated systems, the J&S is a viable add-on for high boost applications. I'll safe your engine eventually. I doubt that you can pull your foot fast enough of the throttle at 25PSI of boost when heavy knock occures. A small drop in fuel pressure due to starvation is all it takes to blow an engine without protection. Same for bad fuel, failing IAT sensors, etc. My Rover would not have survived it without knock controll. I have cracked a liner during a fueling issue at the bigging of mapping it myself. There wasn't more than a slight power fluctuation and it blew liters of coolant at 6000 rpm in seconds though the exhaust. It was the biggest cloud I have generated in my entire life. The fuel pump was not up to the job feeding the bigger jets leading to pressure issues. The wideband lambda sensor data together with the injector duty cycle showed this nicely. I then added a fuel pressure sensor to confirm.