Jay: I just noticed I never responded to your question on 02-15 for which I apologize though by this time I'm sure you already know the answer in that everything tightens up and gets better....bass gets super-tight, fast and more accurate both tonally and w.r.t. attack, etc...the mids become sweet (but not overly so), more accurate, the imaging and high frequency click into place. How are the HDs playing for you these days?
BTW...I recently traded my HDs to Legacy for a set of SEs in Black Pearl. The SEs are fantastic and remind me of just how good the HDs were already but with many noticeable improvements.