I am loving these speakers and can't recommend them enough. I am sure the 2s are great speakers but for rock i really can't imagine a better speaker. The speakers totally disappear and it really feels like the band is playing right in front of you. The nrt tweeter is exceptional...clear, defined and without any fatigue. I prefer it much more than the stock tweeter and for me the upgrade was well worth it. I think the new crossover cleans the base up as well. Special thanks to dina for answering all my questions and recommending the nrt upgrade over the s2 upgrade. I could not be happier with my set up. Ascend is really a first rate company with uncommon customer service. If you are considering the sierra 1 or the nrt upgrade...yes they are that good. Just buy them. As an aside the US made cabinets are stunning.