Don't forget the K701 and Q701 also use different part numbers for the foam behind the pads.
The K702 and Q701 share the same foam pieces.
Can anyone check your foam on the Q701 and tell me what it looks like? Are they both very sparkly and rough?
The K701 pieces should be somewhat softer and not sparkly. K701 and K601 share the same foam.
My stupid Q701 look like it had both K701 AND Q701 foam installed! What the heck..probably no difference.
Does anyone want to be my test dummy?
One thing I noticed is that the every single copper cable (other than stock) I've tried with the Q701 makes it sound thinner than it should be. Still sounds good, but a tiny bit different than the stock cable. The Q701 stock cables sounds almost like Canare and it could be that the Q701 cable uses a higher capacitance making it sound warmer (lower should technically sound brighter and not as warm). It just seems that when I use an alternative cable on the Q701, it loses some of the things I like about it. It took me many, many hours to realize this. It's especially noticeable in games like Skyrim. The Q701 is just not it's old self with any other wire than stock.
I know someone tried it, but try the K702 cable on the Q701. It may require listening to an entire album and then switching back. Probably a huge placebo effect, but maybe someone with golden ears can tell the difference more easily. Even though the K702 and Q701 cables are the same thickness they could be slightly different. Please don't tell me copper is copper. Already heard that a hundred times 
The changes could be a combination of the button, cable and two foam pieces. There's also the internal wires going to the drivers that could be slightly different or maybe a higher gauge of wire is used. Probably unlikely and wouldn't change much.
Edited by tdockweiler - 2/14/12 at 10:54pm