I do not have this grinder but I did have a Mazzer mini (new) I found the standard burrs very slow.
I contacted Mazzer technical and asked about using the SJ burr’s, I was told they would not recommend for commercial use but should be fine for domestic use. I found the 33M much better and used them all the time I had the grinder and the member who bought the grinder carried on using them (even though he had both sets)
I never once had a stall or change in motor sound / speed. I tend to use fairly dark roasted beans.