Disclaimer: This is Inks' pair. Measured couple of months ago, but never had a chance to upload the data. Sorry for the delay, Inks.
A161P is MEElectronics' top-of-the-line IEM with a single balaced armature transducer installed within. Although the manufacturer is well-known for great value per performance products, A161P has been marketed for high accuracy and fidelity.
In order to prove their claim, the manufacturer even has their own frequency response plot, which is diffuse-field compensated, on the product description page. The plot is definitely not of hi-fidelity, but since not many manufacturers disclose their measurement data, such gesture from MEElectronics is very informative nonetheless.
CON: Although the rated frequency response is 20 ~ 20 kHz, A161P only goes up to 11 kHz. The ringing at 5.7 kHz is really audible.