Not familiar with those UXCell earbuds. They look nice, especially for the
price, but judging by Hotboxx opinion, I'd say the Sennheiser MX400's
will have superior SQ for the same cost or less. I put a review up on them here. They don't go in the ear however. For earbuds similar to those from UXCell that have a chance of better sound, you'll have to pay a bit more than $5. Not that much more perhaps. I believe Hotboxx got good results out of some Creative EP630 fakes (a link was posted), and a couple of people I spoke to about these i-Voda's, which are Sennheiser CX300 clones, seem to like theirs quite a bit:
http://cgi.ebay.com/i-Voda-In-Ear-He...QQcmdZViewItem
Not hearing good things about the Koss, though. I'd stay away from that, modded or not modded.