I'll describe the reasons why I modded my triflanges...
I started off with the triflanges at first, but found them to be too uncomfortable. When I switched to the foamies, I found that although the isolation was a bit better, the highs were more peircing than with the triflanges, and the bass response was also less (the foam seemed to dampen bass too much).
I then shortened the transducer tube in the foamies to bring the filter closer to the ear drum in a effort to reduce ear canal resonance, increase bass response, and reduce the profile of the phones sticking out of my ears. The mod did help, but unfortunately, the foam still dampened the bass more than the triflanges, irritated my ear canals (both problems could be fixed by coating the entire foamie with the acoustic layer like the E.A.R. foamies IMO), did not last very long (foam started to lose its resiliance and would not seal properly), and was slow to insert and get a good seal.
When I finally converted the triflanges to biflanges, I had all the benefits mentioned above in a more durable format, but with noticeably less isolation, and the tendency of the largest flange to deform on occassion. The next locical step seems to be adding material to the back of the largest flange to increase isolation and stop deformation.
Beyond that, Shure soft tips or even a custom soft mold may be the easiest route to good fit, isolation, and sound if triflanges and/or modding are not your thing (I still find them to be a bit "congesting" in terms of sound and comfort, and they stick out too much for my tastes). There are posts that are more specific on this topic, but I have not read them too thoroughly yet...
Cheers,
Mark