Subwoofer decibals!!!!!!!!!!!?

um my friend says he has 4 type r 15 inch subwoofers running on 2 capacitors and i think 2 amps running on 4 ohms idk what kind of box he has but probably ported and um he is claiming that he is hitting 163.5 on the meter so is this evern possible if so how and any help is greatly appreciated