From my personal experience with customs, I highly recommend hearing the universal version first since if you happen to not like the sound, it’s hard to sell (a mistake that I have made unfortunately). Like for me, I used to own the MEST MkII and ended up selling it because I preferred other IEMs like the Legend X and Elysium. I am not sure if UM reshells for different owners if someone sells their custom MEST.
I think I have read people are able to get their universal MEST converted to custom. I would recommend contacting MusicTeck to confirm if that is possible especially if you buy off the used market. Maybe they can even convert the custom to universal? Rare for custom IEM companies to do that but UM might offer it for the MEST so I’d ask about that as well.
Another option is buy the used one and listen to it. If you like it, sell that for a similar price and get the custom version. Do keep in mind that the universal will sound slightly different that the custom.
With that being said, the custom version is probably the best version of the MEST since it does take full advantage of that bone conduction driver. Also custom is real comfy and nice since you don’t have to deal with tips.
I am not sure, but I would email them about it. Personally I’d stick with MusicTeck because of how good their customer service is. If things go wrong, might be easier to go through MusicTeck than HifiGo.
I had no issues with mine, but only had mine for about 2 months. It is a flush 2 pin connector, but both connector and cable are quality. You might be able to ask for a recessed 2 pin for either universal/custom which might be more durable.
I personally have had more issues with mmcx than 2 pin, but I have only had 2 pins with high end IEMs so tolerances would be higher
Edit: If you go through HifiGo, make sure that warranty is covered through UM as well. When I bought the DX300 through Hifigo, I realized that they weren’t an iBasso authorized dealer so warranty for the DX300 goes through Hifigo instead of iBasso. It’s probably fine going through Hifigo. I’m personally a bit more careful with regards to purchasing through them even though they’re probably fine. Reason for me recommending MusicTeck is I have had a great experience with them and I’ve talked to people from Europe who have also had great experience with MusicTeck.
Hmmm, yeah I am not sure how much import fees cost for you. Up to you, if you’re not on a time crunch, email MusicTeck and see how much import fees would be