Update after a few days of listening.. the sound absolutely amazing. Of course, it's been around 1.5 months since I last listened to my stock TF10, but my reshelled customs are infinitely better than the stock ones (if not in terms of sound quality, definitely in terms of comfort)! The treble is just as clear as I remember it being, and the bass seems to be less muddy and more defined. These sound quality changes might be minor or even imagined, but one aspect that cannot be disputed is that the customs are so much more comfortable and isolating than the stock TF10. Before, I would struggle to find a decent seal in my small ear canal, then get frustrated with any slight tug would dislodge the IEM. Even if I got a seal, it seemed like it was only a partial seal, much less isolating and "sealy" when compared with my Shures. With the reshell, the difference is huge. Even when compared to my Shures, the difference is large. It's like comparing the difference between sticking your fingers in your ears vs. using deep-insertion foam earplugs in terms of isolation and comfort.
It definitely sucked being without my beloved IEMs for a period of time, and dealing with disappointment when I had to send them back for a refit. However, in the end I have a sweet set of custom shelled TF10 with amazing sound quality and comfort that can't be beat (or beaten?)!