@ OP: I really don't recommend Sennheiser CX series. They just don't sound very good at all. Super.fi 3 does not go in as deep and some others, but it is not exactly a shallow insertion IEM either. I think RE0 will be your best bet. They have the best sound for under $100-$150 in an IEM + a comfortable, shallow fit. They blow the Senn CX series out of the water in sound quality and also beat good budget armatures like PL50 and Super.fi 3 easily IMO. RE0 is just great all around - it has accurate, neutral bass, smooth midrange, fully extended treble and a level of clarity, detail and separation unmatched by any other headphone near that price.