Plastic ring over tweeter opinion

My preference is to tend to stick with what the speaker manufacturer intended or recommends. I use the same logic with power cords - what comes with the component is acceptable to me.

My logic is this: I know far less about these things than the equipment manufacturer's do. I have already made a careful component selection leading to a $$$ purchase. If I find myself beginning to second guess the manufacturer's design choices, my preference would be to change component altogether rather than make any irreversable modifications. (an item that is modified from the original may be harder to sell second hand)

I agree with Shadorne. Mapleshade may make good recordings -- even make decent equipment accessories (I haven't tried them) -- but they certainly don't make other company's speakers, so they should NOT be making suggestions about how to modify them. Ignore their suggestions to remove the phase ring, because at the very least, it will void the warranty, and you may really dislike what you hear as well.

Removing the grill is often a good idea. (But it varies, so you need to try it both ways.) But snipping off the tweeter's wave guide? Giving advice like that goes beyond stupid, to the borders of venal.

This is the same outfit that sells $24 Iso-nad cork blocks that may be procured at your local HVAC dealer for $4-5. Of course, Myrtleshat 'specially' tunes them. Some believe their recordings have not quite achieved near-mythical status as proclaimed on their catalog cover. But audiophile opinions are like ashholes, everybody got one.

BTW, tweeter diffusers are a good thing and an integral part of the driver design. Even the speaker manufacturer doesn't remove them! Then again, Pierre Is a former rocket scientist...

I wonder how they determined it was "as much as 100%"

Perhaps they have a special tweeter meter.

This sounds like a very, very bad idea to me.