You can import it from Hong Kong/China, just beware of counterfeits.
And yes, they still sounds pretty good for what they are, definitely bang for bucks but not best.
I could differ the V6 from CD900ST quite easily:
V6 - Warmer, more bassy, less detail
CD900ST - Treble is bright and bass is more tighter, much neutral than V6, quite detailed and pretty large soundstage. 

My 2 cents.

Can also consider HiFiMan RE400 if it's for female vocal and classical. It's very airy, refined, soft, music flow out like feather.
The HM700 combo with RE400 balance version is even with better details, and larger sound stage. Can check it out. I rated it highly as GR07 classic.

Beyer XP series has large piece of bass, details wise slightly muddy. If you do prefer details and clarity, there are more other options.

Ignore the XP3, 80% of the users didn't get it lasted for even half a year, sounds sub-par. SE215 is a good choice if you want an all-rounder, but it's sounds pretty boring for J-music, I find it lack of air, treble roll-off with slightly recessed midrange.
For your music choices + my own taste, I prefer the Havi Pro B3 Version 1, HE400, they are most suitable plus performance wise. On a side note, Ostry KC06 is not a bad choice if you like a little more air and treble emphasis in your music or ATH-IM50 for a thicker, fuller sound with bass emphasized. 

Ostry is also not bad. Overall performance wise, RE400 is slightly higher range.
If you prefer a more punchy bass, slightly warmer and fuller mids for pop songs, can consider KC06A.
RE400 is good for classical, instruments, female vocal, new age and stuff. It's more to refined, soft, smooth kind of sound signature. It still has adequate amount of bass. But if you are looking for something with strong bass, then it's not for you.

i've gotten the chance to listen to the IM50 and IM70, the IM50 I felt is geared towards bassheads. There's quite a bit of bass to a point I feel uncomfortable with just slightly but will be the love of anyone who loves listening to techno. The bass extends really deep and it's nice but just not to my taste. The IM70 on the other hand is more lighter on the bass, its nice and tight but vanilla wise I think it need's just a teensy weensy bit more bass extension since it already has a nice kick.

Clarity wise I enjoy the IM70 more. I'd suggest you try it at E1's place at Sungai Wang, i'm just piecing together what my memory can pull out haha.