From the looks of things the DBA-02 cable looks similar (but maybe beefier) to the UM2. I like the UM2 for the gym as well, but the E4c cable is great as I use it: Durable, and heavy enough not to get all swinging on me and interfere. That's my main issue with the UM2 at the gym, it's light cable is all over the place...
The SE535 cable is marginally microphonic (very dependent on eartips), and a bit thick / stiff for the gym in the long haul.
So far I'm hearing that isolation is not #1 with the M6 (you, Baycode and others). Great for certain things. But at the gym I'm zoning out and really don't want to hear the disco being pumped into the place or the dropped weights or the whirring of the machines. I like it q-u-i-e-t.
I guess I see your point here. Something like that doesn't bother me as much but isolation on the DBA-02 is definitely better than the M6 and near one of the best isolation I've had with Shure triple flange tips. I had to adjust a bit to the increased bone conduction when I first got them which was surprising for me. The cable on the DBA-02 is still very light and similar to the Westone ES cable I have except the ES cable is better in certain aspects such as build quality, has a memory wire, right angle plug and the fact that the chin slider actually works as a chin slider.