GTRs have 2 knock sensors that are connected to the ECU to lower any chances of it detting its bollocks off.
But fact is thats besides the point, your car aint standard, your running more boost and a FAR less restictive zorst.
And youve no idea how well its set up, even if its setup for the correct octane, you dont know its running right, could be all manor of sensor, fuelpump, injector probs that could make it slightly underfuel n go pop, like any car.
Get it checked if you worried.