I understand that no tuner wants a customer to suffer an engine failure, but we need to acknowledge something important: there are countless variables that come into play after a tuner completes the datalogs and confirms that your calibration is optimized.
If nothing unusual occurred during the revision process, it is assumed that everything is functioning correctly. However, from that point forward, it is the owner’s responsibility to ensure that the vehicle continues to operate properly. Many people do not know how to interpret datalogs, do not understand what a VE table is, how the air-fuel mixture behaves, or which parameters are critical to monitor. Many engines show early signs that something has changed, and owners simply ignore them.
Any good tuner must understand the limits of an engine, and unfortunately, that knowledge often comes with experience and sacrifice. It is the classic “pay to play.” If someone wants complete peace of mind, then they should leave the engine stock.
That said, I believe tuners such as ZFG, Goose, Livernois, TunePlus, and ECT keep their calibrations within the safest possible ranges for daily use.
Every tuned vehicle requires additional care compared to a stock vehicle, and many users overlook this reality.