Wilson is notorious for potting their crossovers, making them difficult to analyze, as well as juicing the response for effect.
Getting a flat, smooth FR out of any of their models will undoubtedly change the sound considerably.
If you still wish to try, come over to the DIYAudio / Multi-way forum and learn about speaker measurement and crossover design. :)
http://www.diyaudio.com/forums/multi-way/
Best,
E