I currently have TORs on. I also have the Ramair filter and a custom tune.
I changed the RPM limit to 6700 last autumn, and was going pretty fast for a few weeks. Especially on the Autobahn, trying out the highspeed behaviour of the Roadster with bags & windshield at full throttle.
After doing that, I have to say the sound of my TORs has improved a lot. While they were almost the same volume as stock pipes in the beginning, they really sound surprisingly good now. They have become much louder, and have a very crisp and aggressive note, especially when the engine is hot.