A little update:
I never quite like the pain job done of the T series. Not that I want my amps to look shiny, but at least not crappy either. T4 is really easily scratchable and I ended up applying a few clear coat myself. T3 is slightly better but still scratchable. The first time when I saw in person the rubber coating on T5, I know it won't last - and it didn't. A tiny chip came off on the first day I got it. Two days ago, when I was trying to turn it on, a rather large chunk of the rubber coating came off right next to the power switch (even from area my nail never touched). Needless to say, I was pissed - almost $200 for this kind of build quality! Anyway, I ended up removing the rest of the rubber coating with my finger nail mostly without much effort on my part. Yes, iBasso - your T5's finish sucks.
Anyway, I ended up taken the T5 apart so I can polish up the bare metal (
looks like steel to me it is zinc alloy, apparently). I decided to leave the rubber coating inside alone in case of any isolation issue. Some fine grade of sand paper and 15 minutes of work later, the new T5 looks better than ever.