Did you read my impressions above?  I'd say the soundstage weirdness they have is coming from the difference in decay patterns between midrange and upper midrange, and also by the "driver dildo".  The soundstage is more natural without it.

Yep I read it, but I didn't think removing the dildo would affect the soundstage much until I re-read the mods performed. I probably should have known, since I have a pair of headphones that had a... reverse dildo D: ... the M-Audio Q40. Removing it also made the soundstage more natural and improved its midrange (more forward, clearer, etc.) It also has problems with enclosure resonance now that weren't so apparent before the mod, so I'm working on dampening the bass because its drivers are of surprisingly good quality.

These aren't half bad if you shave the peak off a bit with EQ, though.  They're definitely not GOD AWFUL, they're just not very good.

Mainly D2. Because it's magnitude higher than the others D3, D4, etc. the THD line usually ends up looking like the D2 line.

Spent a week trying to sell my k550s and then realized that they're new so I can just send them to headroom to be restocked and get a full refund.  Bonafide moron right here.