I was sure to reassemble everything properly. No seams showing by any tabs and both screws went in without issue; also a full grab at the top along the metal support bands... nothing was wiggly.
There was enough bass from my Nuforce Icon HD in stock form before opening the ports, especially if a 2-3 db EQ cut of higher frequencies was employed. Of course, the goal of a mod is to no longer need to use EQ and extra bass would be nice for mobile devices as well.
Maybe the problem is a poor recording. This is actually very possible. Yeah..poor center image in a recording...Huh?!
After several hours of listening last night, center image on "good" recordings does stay centered, but the elements that have been panned in the mix were an order of magnitude wider. I have a large variety of hi-fi recordings in .FLAC from different engineers and they sounded fine before. I'm not sure bigger is *always* better when it comes to soundstage.
Yeah, really... there are plenty of crazy recordings out there and the Q701 is highly revealing compared to most listening gear.
Thanks for the feedback and suggestions, tdock. This was my first time opening my Q and it has inspired me to start familiarizing myself with what internal components tweak the sound in different ways and to tune it more to my liking. Love the amazing value this headphone provides.