I think my J3 should be fine but I have no desire to carry around an amp with me. Although around 85% of my listening is done with my transportable setup which uses my dac/amp so I'm not worried there. The other 15% is with my J3 where most of that is sleeping on the subway :P
The price sounds reasonable. From all indications the cable used is supposed to be superior and many consider the RE252 top tier so I imagine it would be just as good if not better so it's not a bad price. Other top tier earphones are much higher in price and closer to $400 and up.