So, my parents were invited to us yesterday and my father brought the RE-262's. While they're an awesome set of IEMs, truly remarkable for some music (really..they are) I think the IE80's were superior.
Anyway, he brought his tips along, and we traded some. I took his smaller ones and he took my bigger ones, including the foam tips. I still stand behind the notion that HifiMans tips are quite a bit better than Sennheisers tips. At least for me. Even the ones of the same size, single flanged olives, the Hifiman tips did a greater job at sealing and properly isolating than the Sennheiser ones. Furthermore, Sennheisers tips had a bad habit of crawling out of my ears with usage, making me having to push the IEMs back in from time to time while listening, while the HifiMan tips made the IEMs to stay put at all times.
So, basically I'm saying that if you find the Sennheiser tips weird or not especially good, try Hifimans tips. Especially their double flanged silicone tips are real good.