What Ed said...but to add to it...I took mine off last night and wow did the exhaust drone more.
My system drones around 1500-1700 RPM with the brace on, and it isn't a bad drone, and I actually like it. With the brace off i found the car droning from 1100-2000 RPM and it just wasn't a cool drone like with it on...so in that respect, I'm glad I spent the 20 something bucks on the buick brace.
And to also add, I will say that I noticed a pretty nice difference in stiffness to the rear end of my car when I installed the brace. Basically I used to get a little shudder when hitting bumps in the road going around frwy turns at high speed. That no longer happens since installing the brace. I even went out and checked doing the same speed on the same road, in the exact same spot I used to feel the shudder at.
Just my opinion, some cars react more to things like this than other's.