Originally Posted by 1º
i don't see how just an exhaust system can blow an engine
It can't. Such statement the "expert" made is nonsense. ECU adapts ignition constantly, depending on various factors (temperature, humidity, load, etc.). So an aftermarket catback just can't harm your engine.
Oh, and the aftermarket aftermarket software that the "expert" mentioned usually is off the shelf for cars with slightly different mods. In other words usually it is not custom tuned to the mods of the specific vehicle. But it also adapts ignition to a certain level.
If an aftermarket software is too aggressive for the mods, then it results in knocking and can harm your engine.