Actually, they do sound different. Apparently, there are two different versions of the meelec gray balanced bi-flange tips. I asked joker before and he said he was sure they're all the same but they are not. I ordered the so called "balanced tips for m9" right before they ran out of stock and I guess they didn't have 3 pairs, so 1 of the pairs was what meelec has now on the site as gray balanced double flange trips. The one "for m9" are harder and with overall darker one shade of gray while the other are in brighter gray, softer and the opening of the tips is slightly smaller and in a darker shade of gray. They sound different and the "for m9" version has a lot better seal and thus better bass and netter everything - the softer ones are just sub-par compared to the other ones and useless for - it's really a good thing I didn't receive 3 pairs of them.
Here is a pic I just snapped for comparison (the quality isn't very good)
GR02 BE stock bi-flanges (left), meelec balanced tips for m9 (middle), meelec balanced double-flange tips (right)
Of course, I'm not 100% sure if itt in't the other way around and the softer version on the right is the "m9" version and the other one the "balanced sound". I just go with what I ordered - the "balanced tips for m9".
Edited by kova4a - 8/14/12 at 12:43pm