I'm afraid my tips are nothing special. I have collected a number of different shapes and sizes of silicone tips over time, so I always play around with different tips. I'm often surprised how much of a difference it makes. but It makes sense really. everyone has different shaped ears. I believe the ones I settled on being my favorite may have come with a head-direct iem purchase at some point. but they really could have come from somewhere else. I also chose these because the opening inside is bigger then some tips. I would have liked to try to experiment more, but time gets away from you. I finally had to make myself sit down tonight and get some more good head time with these. anyway, here are some pics to compare what I am using. the grey are mine, the black are the Large originals.
Another thing I found when listening to these is that you also have to rotate them in your ear to find the best spot. this comes I'm sure from the fact that the speaker opening is not round, but oval. If you just stick them in your ears and expect everything to work, you might miss something. I found they work best for me slightly rotated forward (so that the cable moves closer to the jawbone, not down to your earlobe)