I did not like the black included foams which are the longer, standard T-series. I prefer the shorter, rounded TS-series. They give me a more open sound and it's less "directed" towards my ears. Maybe it's just my imagination the thing about being less directed but they do give me a less closed in feeling. I also noticed why I don't like stock silicone or auvios as much. They tend to give the bass more emphasis. Coupled with the treble being stronger, the relatively stronger mid bass makes the upper mids seem too distant for my taste. They do become more aggressive but also are also tilted towards bloated to my ears. So I prefer the Comply TS-(400 or 500, both should actually fit) for their more relaxed, smoother and more neutral sound. The two conclusions I draw from this are:
1. We all hear things differently and appreciate different things.
2. Different tips fit some ears better and other ears worse and only by knowing your own anatomy, personal ear canal resonance characteristics, tip material and nozzle diameter and iem frequency response can you understand and predict the outcome without trying. Some rules are more or less general. Like the material, bore diameter, insertion depth etc. But you need to experiment to know what fits you.