For the isolation, all you need is the tips that come with the ROCK zircon. The zircons are very cheap, so... shouldn't be a problem. That combo is the ultimate combo, and makes ANY other chi-fi IEM pointless (IMHO). Also, Tin Audio are working on a T2 PRO, that will have more bass (if that's your thing), so you could wait for those to release as well.
The problem is not from the tip only, but because it is back vented, so it will always bleed a little noise, unless you put earmuffs on top of them.
The T2 is one of the best iems under 100, especially in cold sounding balanced neutral category, but the sound character is not for everyone and not for everything. So to say the T2 makes other chi fi pointless is very subjective.
I love the T2, but i also think it is not "the ultimate" better than all other in my collections. The King Pro and Kanas are more mature sounding and more coherent (but one can argue because they are in a different price point), and the Svara Red (more or less same priced) is more enjoyable for warm sound. Even the Einsear T2 (cheaper) has it's own special place