Thank you for the info. I've tried out both JVC and AUVIO's tips. To me AUVIO's are far superior in everyway. JVC couldn't give me any good seal and the sound is horrible. AUVIO on the other hand, they provide excellent SQ. Now I am having difficult time to decide which size to stay with. M and L both works for me, L provides complete a seal, more bass, while M still offers good seal but not as good as L and bass is noticeably lighter but they are a little bit more comfortable.
I don't believe that Sennheiser designed these to have that 'complete seal' that everyone talks about. Thanks to Burtomr I have been experimenting with both the large and medium Auvios. At his behest I switched to the large and noticed an increase in bass and a decrease in soundstage and clarity. I used them for a month then, on a whim, I switched back to the mediums. The increase in soundstage and clarity was distinct and there was a slight decrease in the bass but I discovered it was one I could easily live with as comfort was improved. Clarity is important to me as I listen to a lot of classical music so it's the mediums for me. Others may prefer the increased isolation that the large size offers. I might have ago at Burtomr's customisation idea.
The real test for me will be in late September when I take a five and a half hour flight to Perth. It might be that the large will fit the bill much better in these circumstances as I want as little plane noise as possible. The best headphones I've used to minimise aircraft noise are the Senn HD280s. I can't hear anyone speaking to me even with no music playing so they will be the benchmark
FInally, what is the indisputable in my opinion is that the Auvios are the best tips for the IE80s