Nice Review!
So among these 3 headphone MDR-1R, Momentum and M-100 are the closest to the Th900 sound sig cauz I am looking forward to get a Headphone that have near TH900 sound for portable use

That is a hard one to answer. The TH-900 is really in a different category. There are many other aspects the TH-900 excels in such as resolution, detail, smoothness, imaging, and even wider soundstage, subtle texture in presentation, etc. I honestly find it hard to find something around the MDR-1R/Momentums/M-100 price range that comes close to the TH-900.
I'd personally say the SigPros probably closer to the TH-900s and even then, it's probably still not that close.

AnakChan, how well suited is the MDR-1R for jpop, pop, soft rock, and classical? I'm wondering whether to buy these, the amperiors, or the dt 1350 (although I've heard that there have been padding issues with these). The only headphones that I've had for a while are JVC HA-X570 and Philips SHL9500 (although these are no longer in production and the left cord snapped). I'm not that much of a bass head, and I'm not sure whether the amount of bass is due to primarily the headphones or the type of music/source. As for speakers I've had the Yamaha YSTM8 for quite a while. If you could reply, that would be great. Thanks for the awesome review so far!

Ah, and I've played the violin for quite a while, so I probably won't be able to tell if the treble is too forward. I'm also not sure if a pair will be too bright.

Very good review. These are exactly what I'm looking for!

Thanks for the review. I heard these briefly(~15 mins, probably not broken in) through my Galaxy S3 LTE and I thought they were on par with the AKG K550s on SQ (AKGs may have an edge on neutrality) and isolation, but more comfortable because the chamber is deeper and the diaphragm didn't brush my ears. Pricing over here (Singapore) for these two 'phones is about the same.