Hi guys, I'm looking for a custom IEM recommendation and would appreciate your help. I've been a member for a long time, but haven't posted for a long time. I usually only drop into the Head-fi forums when I'm looking to buy. I end up reading dozens of reviews, getting confused, and buying something random. A quick rundown of my experience with decent IEMs/cans: 1) My first IEM was an Ety ER-6i. I loved the clarity of these phones. I loved their tiny size. I loved their isolation. I disliked their anaemic bass. 2) After the ER-6is got stolen, I bought my second IEM - Future Sonic Atrios M5. These had awesome bass, but I disliked everything else about them. They sounded muddy next to the Etys I was used to and the mids sounded a bit too recessed. They had a very sharp peak in the upper mids/highs at the same frequency as trumpets, which made any track containing brass instruments painful to listen to. 3) I sold the M5s and moved towards over-the-ear cans. My girlfriend had two pairs of cheapish Sennheisers which I thought were pretty good, so I moved a couple of steps up the Senny chain and bought a pair of HD 25-1 II cans. I still have these and they are bloody great. They have excellent bass and a pretty flat response across the rest of the spectrum, offering a natural sound with just enough mongrel in the bottom end to get the feet tapping. They also have very good isolation. They lack a bit of soundstage. 4) The Sennys were a bit big for commuting and travelling, so I bought a pair of Vsonic GR-01 IEMs. I liked them. They sounded pretty good in that they didn't have the weaknesses of the other IEMS I had owned. They weren't as good as the Sennies (although they cost nearly as much), but for IEMs I was happy. However, I did have some fit issues with them (as I did with my other IEMs) because my left ear is a funny shape. And there was something just a little bit lacking with them ... 5) The GR-01s got stolen. Mostly I listen to my Sennys, but I frequently travel, I sometimes commute, and I am about to take a year off to do some major hikes. Over-the-head phones are too big and heavy for this. So ... Given my fit issues with IEMs, I've decided to splash on some customs. I have absolutely no experience with customs and have no ability to audition them (I live in Malaysia). My criteria: - Price: I'm happy to spend USD $500. - Sound: Just remember that I like the Sennies, dislike recessed mids, dislike unnatural spikes in the mids/highs. - Isolation: Prefer very good isolation for public transport - Amping: Prefer phones that sound great without amping - Source: I currently have an iPhone 5s. No doubt this will change in future, but in any case it's likely the customs will be driven by smartphones I've read lots of reviews, including the massive comparison by ljokerl, but came away overwhelmed. I've been looking at some of the cheaper options in Singapore, such as the Null Audio Advanced AcousticWerkes A3H-V for USD $440, but at 42 ohm impedance these might be a bit hard to drive without an amp and I can't find any reviews. Even the GR-01s were a bit hard to drive at 32 ohms (source was a Sansa Fuze). Thanks in advance for your time, guys.