I modded it because of all the positive feedback I had from people I trust that did the mod. For me it smoothed out the sound ever so slightly, and I liked the change, not that I didn’t like the sound before. It’s a very subtle change, unlike the HD800s which I heard on my system and didn’t like. Unlike the SDR mod, the 800S messes with the bass in a way I didn’t like. So as far as I’m concerned Sennheiser fixed nothing. For what it’s worth I’m not a Senn fanboy, the 800 is the only one of their headphones I really enjoy. In fact for what you can buy it used for today, it’s probably the biggest bargain in head-fi right now. If it needs to be said this is my personal opinion, and just happens to be shared by many enthusiasts far more knowledgeable and experienced than me.