Most of the Ninja's work was done on av123's speakers and those that followed him from there loved his changes from what I remember.
I did the one and only (as far as I know) Ninja upgrade to my M22's and they did indeed change the sound(no surprise), but I didn't think it was better, it was simply different, not my cup of tea as they say. According to Sean the new crossover point was moved farther up the FR to reduce ringing on the 5 1/4 drivers and so on, he was all about the measurements. Once I was done with the XO's I pulled them out and sent them to Ian for his impressions, measurements etc. I am sure my original postings about this experiment are still kicking around here. I still have the crossovers out in my garage storage bins. I want to make some speakers one day to use them in.
Personally I thought the ninja was just having some fun playing around with the crossovers and making some already good sounding designs sound/measure better to himself and his help, all the while hoping to make a business out of it. I saw nothing wrong with his desire to make these changes but also felt he had some questionable/unprofessional dealing/tactics/episodes online.
As with other companies that claim upgrades make an audible improvement in sound, I have looked on these sites such as "Ninja's" and with these alleged better crossovers and costs to do them often exceeding $500, I can't help but keep asking the same question over and over again, if one wants better performance, why not just apply this money toward better speakers?