[TRapz]

This spring I'll be getting IEMs, which I'll likely run from a FiiO X1 (if not, an iPod 5.5G into something like a Topping NX1). After searching for months, I had settled on an IEM; then, after going to my first meet, realized I wanted a warmer sound than that IEM would likely give me (Havi B3 Pro 1). I don't know how much I'll be getting for Christmas, but I know I'll have at least $100 to spend on an IEM with money I've already got. Anything between $100 and $300 is fine, but as always, spending less (possible on Head-Fi?) is better. Here's my requirements:

1. First, isolation. I'm on an insanely loud bus every day, and it's where a lot of my listening is done. I hate having to turn up my music player because I fear I'll hurt my hearing. The more isolation, the better (the IEM MUST have at least good isolation).
2. Second, the sound. I'd like something a little warm, but not overly bassy. I listen mainly to rock and don't want guitar solos shoved behind everything else. I also want to hear the drums, being a drummer. I also like upfront vocals; no V shaped sound signatures. Soundstage should be at least okay, not totally flat. Separation MUST be good, it shouldn't be a garbled mess. Everything should also obviously be very clear, no veil or anything.
3. Build quality is also very important. I'd like these to last at least a couple years; detachable cables would be a huge plus.

 
I listen to anything from Jason Mraz to Metallica to CHVRCHES to 50 Cent, 90% in WMA Lossless, so the IEMs don't really have to be forgiving. These are the IEMs I've considered; keep in mind, I haven't tried any:
 

1. Shure SE215: Seems good, but maybe a little old now; isolation seems perfect. I'm afraid they're a bit outdated now, and that similar sound quality can be achieved for less money. I have a thread here discussing that.
2. Hifiman RE-400: The sound signature seems good, like the SE215, but build quality and isolation are major concerns. These I'll likely not get. 
3. RHA MA750: These seem like great headphones too, but the metal design will get cold here in the winter and I don't know too much about its isolation.
4. Audio-Technica ATH-IM70: Reviews show that this IEM is almost perfect for me, but the large design isn't very attractive (comfort-wise), and again, I don't know too much about the isolation.
5. Shure SE425: Pricey, might not have enough bass, but neutral is okay too. The sound quality itself appears to be very good, and isolation, like the SE215, is said to be great. Build quality seems great.
6. Westone 3 (or some 3rd IEM in one of the Westone lines?): I've heard a lot about these, but don't know a lot. Very pricey, but isolation seems great and I've heard that the sound is very good too. Likely not to buy because of price, but Westone 2 (or UM 2 or W2, whichever) might be possible if they're any good. 

 
If there's any other IEMs you can think of that meet my criteria, please respond with a very short description so I can do some research on them. If there's anything I've missed here or anything you want to suggest or add, please do so. Any response is very helpful, thanks for reading and responding.
 
TL;DR: I want well-isolating IEMs with a slightly warm sound that's still near neutral for under $300.

 

[TRapz]

Update/Bump: Really leaning towards SE215. Any other opinions/suggestions?