The MDR-7550 and MDR-EX800ST are exactly the same IEM (the only difference being the latter is sold in Japan/Asia). There is indeed a 7550 thread and a few EX800ST reviews/impressions scattered all over the place, here's one of them.
FWIW, I personally prefer the EX1000, followed very closely by the 7550/EX800 and then the EX600. SQ-wise, all 3 IEMs are definitely members of the same family. To me if, say, I gave the EX1000 a rating of 10.0, the 7550 would get a 9.5, and the EX600 a 9.0. This would, in turn, make the EX600 the best bang-for-the-buck of all three.
Thanks for the link.
I actually started reading when you first got the 7550 and left off when you received your ex1000 back.
Seem different presentation.