Just did some logging/tuning. ~4.5 FATS, and two SS Camaros didn't want to race :)
#27
To answer both of your questions...
Yes, it makes the ride quieter, but what it does for the accoustics is worth every ounce of weight. I'm still using my stock Bose Symphony and people who have heard it in my car literally cannot believe it is stock. Btw, I'm not sure about the exact weight but it's prolly less than my spare wheel and tire, which is prolly 50lbs. I keep good tires on my car so I'm willing to take the chance with the spare, but after hitting a pothole the size of a crater the other day in my wife's Mercedes and literally bending the wheel beyond repair, I'm tempted to put it back in.