Concerning the request for a TDK IE800 vs Havi B3 comparison, I used Foobar2000 -> O2 amp -> IEM for the session. This post is more directed towards the person who requested it, but anyone is welcome to use/comment on it. I apologize for posting this later than I had expected, but here are my findings:
The TDK IE800's treble is fine with thick tips and sounds comparable to the B3's treble with the Senn double flanges. I got curious when flib372 said that his/her IE800 has metallic treble, so I swapped over to the Senn double flanges. I couldn't stand the treble when there was supposed to be sparkle on some tracks, because it was really really hissy. I switched back to my normal thicker tips for the IE800, and I'd suggest anyone finding the IE800's treble too metallic to do the same.
The mids on both were very similar, except vocals were more forward on the B3. The piano had slightly more natural decay on the B3, but strings sounded more or less the same on both. The B3 has more bass quantity (both mid- and sub- bass), but I cannot comment on bass quality since I'm not very good with this stuff. The soundstage on both were actually comparable, and I didn't really notice how big the IE800 sounded until I did this comparison session. However, instrument separation on the B3 is better, which also contributes to the vocals sounding more forward, I believe. Drums sounded more "in your head" for the IE800, while they sounded to be coming from the entrance of your ears for the B3 (not quite "out of the head" yet, though).
All in all, the tuning for both IEMs seem really similar. Depending on what you prefer for the differences in each and how much you are willing to shell out for a small upgrade for a similar sound signature, I don't think it's worth another $60 unless you are really curious about it. You're probably better off using/buying a pair of thicker eartips if you aren't using some already. If you still don't like the treble on the IE800 and want better instrument separation, then by all means go for the B3.