well, I wouldn't be too optimistic about this(sorry). I have the RE400, and they're really not something I would think about to explain any etymotic product nor would I suggest to any owner to get an er4. I hope you'll like them and see all their differences as a nice change, but given most of your IEMs, I would probably have tried to discourage you from getting a pair of er4.
What do you suggest is better than the "legendary" ER4 then?