^ I can only comment on the last part of your question. My EX1000 are loaned to fellow HeadFiers, but I'm currently evaluating the EX600. As it stands, they exceed my expectations by far and (without the chance to do a direct A/B) I'd say you get about 90% of the EX1000 for less than 50% of the dough. Btw there's an ongoing discussion about the EX600 in this thread if you're interested, in which the OP concluded very eloquently:
... and I wholeheartedly agree.
Now what has all this to do with the A846? Well, I've been auditioning the EX600 during the last few days using my Sony A845, Samsung R0 and Cowon i9. Thing is, for some odd reason their bass sounds pretty boomy with the Sony and noticably tighter (and a bit leaner) with the R0 and i9. To make things worse, you can't effectively EQ down the bass on the A845, since the lowest band is centered at 400Hz and ClearBASS only allows you to add more bass. So bottom line, IME the EX600 have rather bad synergy with the Sony A8xx. Of course I don't claim that it will be the same for the EX1000, but considering how close these two IEMs are, it's very likely.