Hi,
Over the years I tried many Iem, including Shure, Etymotic etc...
In 2010 I tried Avery Customs Ear Plugs. They make it for arround US$130 and are very good.
You have to send to them your ear impressions, and also they have a list compatible Iem units.
First I made one for the Etymotic HF2, and was very good.
In 2013 I made another for Westone Um2, and it was better, but not perfect. (You don' need to send another ear impressions, as they keep it for you)
Maybe next year I will make one for Shure 425 or similar.
I purchased also Cosmic Ears BA-3 last month, they are very good sounding, but no suitable for running. There is a air flow inside the ear, and also noise with swet contact with the hard case of the iem. Sad, beacause the BA-3 sound much better than the combos above.
Antonio