Nice write up. As most of us have a pair of the Blon BL03; the comparison you made to them helps in interpreting your findings on the T4.I wrote a short review of the Tin Hifi T4 on headfi: https://www.head-fi.org/showcase/tin-hifi-t4.24037/reviews#review-22964
I learned (the hardway) that Tin HiFi is not a home run for me, after cycling through three iterations. I did end up keeping the T3, with the tape mod, as I was relatively new to IEMs and was enamored of the stock cable.
The T4's successful campaign made me pull out the T3; (as I hadn't touched them for almost half a year) they were much more to my liking, when paired with my Radsone ES100 (BT amp) and some EQ manipulation, vs. direct connect to my Note 4 phone.
I almost succumbed to the T4 promotion, but I felt that they would probably be an incremental tuning (as your findings support), at best. I'll probably try again, somewhere around T7/8.