I have the AV8801 and have seriously considered purchasing this kit for several reasons.
1) It allows you to turn off MRC Mid-Range Compensation which is Audyssey putting a hole in your frequency response graph ~1.8 kHz because they are stuck on a 65 year old advice by the BBC that speakers suck and need to be helped in this mid-tweeter crossover region. Why, Audyssey, why?
Audyssey already told you why, the same 65 year old reason you mentioned lol..
By the way, I also have the AV8801. I plotted many graphs with my Umik mic and found that little notch or hole people have been spreading around on forums are really overrated to the nth degree.
I can hardly see it on the graphs Audyssey on, off, flat you name it, it is not significant at all yet people made such a big deal of it. I do wish Audyssey give the option to get rid of it just to calm people down, though in reality, moving your speaker by even an inch probably has a more pronounce effect than that little notch. It used to bother me somewhat (mostly psychological
)but not any more after I saw the FR response graphs with my own eyes.