Didn't hear the R3 but based on the review I read it does not seem to go well with all genres:
A portable amp could improve soundstage but would cost you as much as a good IEM.
Plus it would it reduce portability with it attached to your Nokia device.
Best course of action here would be to dedicate all your budget to the best possible IEM.
You could always invest in an amp later if really needed.
Regarding the lost E30 tip, Comply foam tips would do the trick but also increase bass (careful)
Select tip finder on the top of the screen, they have the E30.