Hi all!  I've loved your reviews/information for some time and finally need a bit of specialized advice.  My UE triple fi 10's are finally dying and I'm looking for a replacement set of... something similar. I've tried the Audio Technica ATH-IM01 and ATH-IM70. I thought the 01's were a little digital and shallow sounding, lacking in the low end. I really like the way the 70's sound but the isolation isn't enough and the fit of the headphone shell hurts my ears.  Now wondering if the ATH-IM02's are the way to go?  Maybe the DUNU DN-2000 but unsure of isolation here...  HELP! My brain is going to explode.
 
Budget: $100-$300
Source: Usually a first gen nexus 6, sansa clip+, or nuforce dac/amp depending on the day/battery power/location of my activities.
Requirements for Isolation: Maximum. I work in a loud metal shop and need the most isolation possible to enjoy music and also protect hearing.
Public: yes
Preferred tonal balance: Flat or maybe a little warm
Preferred type of headphone: IEM - leaning towards balanced armature due to isolation requirements. Also highly prefer over ear/replaceable cables.
Past headphones: Klipsch custom 2, UE triple fi 10
Preferred Music: Lots of stuff. Everything from metal/punk to folk, electronic, and audio books. Improvement from my current set up: Functionality. Mine are cutting out in the left channel (yes I tried new cables and other sources). Punchy bass, clarity, something to rock out with.

I think I've narrowed it down to Shure SE425, Audio Technica ATH-IM02, Sony XBA-A3 or Sony XBA300AP.  Any thoughts?

forget the Sony A3 if you're looking for isolation. 
the IM02, if you liked the 01 fit and isolation, is a good option. Shure and Westone shells are excellent. maybe the W20?
have you thought if Custom IEMs or even Custom Sleeves ?

I've thought about the custom route but seems to be slightly over my already extended budget.  I guess there are just too many decent options with no clear 'best' option.  Thanks a ton for your reply.  This has been killing me