All the x-pipes will make +/- 1hp on the dyno. "True-X" vs. Stamped X will make no difference in power, True-X pipes are just marketed that way to be percieved as superior because it is a newer design.
And my car can gets pretty damm loud, but clean loud, not race-car eardrum shattering loud, loudness has alot more to do with your muffler type.
At first, yes. I suppose it has gotten louder over time as most exhaust does, but the volume wasn't that much louder than stock at first. Keep in mind that I'm around loud cars everyday so my judgement on volume might differ. I can tell you that even though it doesn't sound THAT much louder inside the car, whenever I hear it echo (concrete freeway walls, parking garages, etc.) it does seem pretty loud (and might I add sweet!).
Don't get me wrong, I'm not by any means trying to steer you away from getting one, I'm just saying that at first it wasn't what I expected...