I just got the E4s and I'm liking them very much. I would like to use the foam tips, but I'm finding them to be a little too small for one of my ears, since my ear canals don't seem to be the same size.
I used to have the e2s, and those foam tips fit just fine, but they were bigger than the e4 foam tips, iirc.
The triflanges don't seem to work well for me, and the comfort rubber tips seal really well, but I find them to be a little bright. I am assuming that if I could get the foam ones to fit right I would get more isolation than the comfort rubber tips, and I do like the sound of the foam the best...though I think for some music the rubber tips might be better.
Anyway, is there a foam tip that is thicker (I think it's more a thickness issue than length) than the stock ones that will sound the same as the stock ones--that is to say, that there wont be so much foam that it has a negative effect on the sound.
I have been using cut down regular sized ER4 foamies as these seem to be a firmer fit that the shures.
I do have some issues with sssibilance at times and jamming the cut down foamies in as far as they can go does help with this.
The full length are easier to insert securely but tend to emphasize the frequency areas that annoy.[for me]
The ER4 foamie diameters are 10mm for the small and 13mm for the regular black, I cant find any info on the large yellow but would assume they would most likely be another 3mm step up to 16mm.