Well, I have two quality 10" subs running off a JL 1000/1 in the Z... my car is louder than most you talk about, BUT I got the whole car dynamatted, so despite the noise level, it gets kept inside the car.
And yes, I too am tired of seeing baby blue ford explorers with altezza tailights and 4 15" subs that cost $20 each running off a crappy amp that might have costed $100...