Looking to change from He-400i to HD650 - Wise move?

Hi all,

So I'm working my way up to 50 posts with the aim to put these up for a trade/sale.

I'm wanting to move to something more like the HD650 and what sort of change should I expect? Would this be considered a good move or what? I prefer a slightly warmer signature that the He400i's are obviously not designed for. Perhaps even something closed.

What sort of headphones would you suggest that I trade/save for here in SA?

Thanks all!