They're Fing with you, in case you didn't catch on. //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif
You said a statement which was false so they followed it with more...call it hazing if you will.
It's all in the motor. A sh*tty motor is still going to sound like a** be it a 10 or a 12, 15, or 18. Just like you can still get nice lows out of 10s, 8s, 6.5s even. Install dependant of course. Oh and speed between different sizes is a myth. A 18" will play the same notes as quick as a 10" with the same motor and suspension.