I spent about a year trying to get a good integration between my Magneplanar 1.6s and the Vandersteen 2Wq. The good news is you can get a pretty good match by varying the Q setting. The bad news is you have to put a capacitor in your signal path as a first-order high-pass filter. The original W-4 box lets you vary the capacitance value until you get a good match with your amp. Despite my amp being nominally 100k input impedence, I found a 50k setting worked best. Then I replaced the switchbox with the specific X-2. Unfortunately, it make a big audible impact. I ended up using a Dynamicap instead, for a more transparent sound.
YMMV
doug