I have found that the largest stock foam tips give me the best bass. Dekoni does nothing for me. Xelastic are very comfortable, but lose the majority of the bass. Spinfits and Dots lose the bass too. I ordered some Final Type E, should be here any day now.
A VERY tip dependent IEM.
Symbio W Foams are my preferred because that happens to me with the bass as well re: those tips.