Za_WarudoAccording to the website, the Harmony non-pro has a similar signature to the HD650.
Similar earphones/headphones (signature-wise): HD650, Sennheiser IE80, Westone 4, 1964 Quads
Za_WarudoNo limits in quantity.
H8 non-pro is similar in its lushness, slight darkenss and smoothness to HD650. I've never heard RE400 so I'm sorry I cannot compare.