Depends on what pads are being run... stock pads will leak more than proper fitting overear leather ones. Fostex cable is way better than the stock janky, microphonic one the DT-177X comes with...TH cable is a premium feeling, plyable soft-cloth sheathed cable that is virtually indestructible and way less microphonic. The DT-177X cable is way too short for my needs, why I had an 8' custom cable made for it.
Main reason you go for a Fostex TH/TR is their glorious subbass that you simply don't get from most any other headphone... clean subbass impact that hits like a freight-train and overall warm yet bright sound... The DT-177X is subbass light in comparison to a TH-X00 Purpleheart...