Any way you could get your hands on some sample sizes of the screen? This way you could drap them over your W22s and see how much it affects the SQ. If it doesn't affect it much, I don't think it will, you can feel more confident in moving forward with the M60 purchase.
BTW, I beleive the M22 actually sits about 6-8db down at 60hz, which would also explain some of the lack in mid bass, and I suspect the W series is even farther down than that due to the lesser volume of the housing. Try bumping up the crossover to 80 on the receiver and see what that does for you.
