Hi guys, I have the chance to buy the hifiman sundara NEW with 2 years warranty for 303 euros from the most reliable audio store in Italy that I know of, which also offer 30 days free return (discounted price from hifiman + a discount code I have), the promotion ends in a few hours. Now, I'm a happy Sennheiser hd660s owner, which I drive from my Sony walkman nw-zx300 balanced out with satisfying results. The price for the hifiman is appealing though, would it be worth to own both? I suspect I might need to buy a decent amp to properly drive the Sundara, while I don't feel the 660s really need anything more than the walkman balanced out. Long story short, I'm afraid that the Sundara might end up costing me a lot more than 300 euros, at least 100 more for a balanced cable to get the most out of the sony zx300. Also I don't know how the mids comprare between the sundara and the 660s, I love the mids of the sennheisers, if the bass on the sundara isn't substantially better, I think I will pass on this. Do you guys have any advice? Are the two so different?