Update:
Zero Audio Carbo Tenore > TDK BA200 > Monster Gratitude > VSonic GR07 MK2 > Zero Audio Carbo Basso > NuForce NE-700X > Hifiman RE-400 > MEElectronics A161p > Audio Technica ATH-CKN70 > Philips SHE3590 > Hifiman RE2
IEM comparison
TDK BA200 (stock comply tips).
VSonic GR07 MK2 (largest stock purple tips)
Monster Gratitude (Meelectronics double flanged tips)
Zero Audio Carbo Tenore (Meelectronics double flanged tips)
Zero Audio Carbo Basso (Meelectronics double flanged tips)
HiFiman RE400 (Meelectronics double flanged tips)
Music preferences: Rock and Pop.
Treble: Gratitude and GR07 MK2 sound the brightest, then Tenore, then Basso, then BA200. I think the RE400 is equal to the Gratitude/GR07 MK2 or Tenore, but don't recall exactly. I found that the Gratitude was tuned too high (e.g. snare drums sound too bright). BA200 treble is too smooth and not enough quantity. Tenore is my favorite in this category because they aren't as smooth as BA200 and not as harsh as Gratitude/GR07 MK2.
Mids: For vocals, the best are Tenore and BA200. Female vocals sound like they are in the room singing to you and are so buttery; gives me chills. I give a slight edge to Tenore because they sound more airy. Gratitudes are clear but singer sounds farther away.
Bass: My favorite in this category is the Gratitude. In terms of quantity, Basso > Gratitude > Tenore > BA200=GR07 MK2 > RE400. However, I found the Basso to have too much bass and not as good mids. Gratitude has the best quality bass. For my tastes, Gratitude and Tenore have the quantity that I desire. Tenore bass hits hard enough and is punchy. Bassos have too much and BA200, GR07 MK2, and RE400 have too little.
Detail: GR07 MK2 and Gratitude have the most detail (and maybe RE400), then Tenore and Basso then BA200.
Efficiency: GR07 MK2 is the most efficient, then Gratitude, BA200, Tenore/Basso. Don't have the RE400 any longer to compare.
My favorite is the Tenore because they sound the most natural and true to life and they have the combination and quantity of bass/mid/treble that I desire. Female vocals give me chills and have the most texture. Next would be BA200 (smooth and great mids) and Gratitude (big and energetic). Basso has too much bass and GR07 MK2 and RE400 had too little bass and sounded a little boring.
Improvements to my favorite 4 that I would love to find
Tenore: Would like slightly darker tuning (but not as dark as BA200), and bass quality of the Gratitude
BA200: Would like more bass, more treble extension.
Gratitude: Love the bass quantity and quality, detail, and treble extension. Wish they were tuned darker so that they would sound more natural and true to life. Snare drums too bright sounding.
GR07 MK2: Would like more bass (maybe I'd like the Bass Edition?)
Tenore is close to perfect, but would love to find one with incredible vocals, have life-like tuning, quality bass and decent quantity bass, and detailed, but slightly smooth treble.