I have a 12" GTI MKII running off of a crown 1100.1. I love this setup. It's the 3rd sub I've owned (I've had an RE SE, Eclipse Ti, and now this GTI.)
It's def a very musical sub that gets extremely low in my 1.2^3 sealed box. I'm thinking about buying a 2nd one as soon as I pay my debt off for buying the crown amp //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif.
oh it def moves....I really can't say much for how they sound ported b/c I only heard it in someones car( the guy I bought it from) for a minute or so. It did get loud for a single 12" but it was just playing radio stuff and I don't even know the box specs of what he was using either.
as far as taking a beating...yeah it's taking the 1100.1 decently but I had to back off on the gains a little //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
well in sealed(1.2^3 no polly fill) it gets extremely low with authority. Normal notes it doesn't do to bad. If you are wanting to bump rap or something, it does enough for me but maybe not for people who like ported.
It's definitely a music lover's sub. It is NOT the loudest sub out there, but they are fantastically well designed, very accurate, and have more than enough output for a musically oriented application. I can't imagine any person who enjoys clean, accurate sound being disappointed with this driver.