The
Rose Technology Mini2 and
Brainwavz B200 are models that score really well (the first one is more tuned for tonal balance while the latter has got a somewhat richer and darker tone), also when it comes to soundstage (although they still don't match the MR3 when it comes to 3-dimensionality and expansion). The
MR2 would do the trick when it comes to soundstage (it's a bit bassier than the MR3, however without the ~ 5 kHz elevation, while the ~ 8 kHz emphasis is still there), but I'd say its technical abilities are a bit below the Rose's.
If you were about to cross the $200 border, the Eternal Melody EM-2 UIEM (that can be individualised just as much as the CIEM version) would offer some richness that is about similar to the B200's, but more treble than the Brainwavz that is more on the darker side in the highs (the EM-2 sports a 7 kHz elevation). While it doesn't fully have the Pai's soundstage depth, its width is just immense with a very wide spatial basis (I'm not exaggerating if I say that it goes from my far left to my far right shoulder and clearly leaves my head) that exceeds most of what I have heard, especially in this price range.
I think that the most clever decision with a $200 budget limit is to get the Rose and inexpensive but technically very profound Brainwavz B100 (the B100 isn't in the same league as the B200 when it comes to technical abilities, however it is a great single-BA IEM that roughly shares the B200's signature).