I did swap the stock foam out with Viva paper towel (one single square). Now don't ask me HOW on earth it's possible, but it seems to sound better than stock. This is after listening to it for 4 hours now!
It seems much clearer than stock and smoother sounding with harsh/fatiguing recordings. I swear it's imaging is better, but that's nearly impossible you'd think. Maybe it just reduces the soundstage and has fooled my brain somehow? It seems about the same size. Not any warmer at all than stock foam.
I can't even figure out if the Viva or stock foam allows more air in. The Viva doesn't completely close off the grill. There's still a few corners exposed.
Basically same as stock, but a bit clearer it seems. Crystal clear now. Maybe some other minor differences. Right now it's almost sounding like a super clear HD-598 with more detail and more forward upper mids.
The Q701 has far better bass though. Probably more mid-bass as well.
I'm not going to over-analyze the differences with paper towel for hours, but i'll leave it as it is since it's sounding so good. Maybe do a quick check of stock foam when I have more time.
With my setup right now, I hate to admit it, but the K601 seems a bit worse. The K601 seems a bit more flat, but not as fun to listen to. Then of course it does have some random peak that only seems to show up with garbage tracks.
K601 does seem warmer, but I don't know how I ever thought it had more bass than the Q701. Ugh..it almost seems dark compared to the Q701. Perhaps a bit more treble than my HD-600.