I think that disk with the small hole in it comes out without a detrimental affect on performance. Also check the shower head itself for small holes.
The alternative is to go with an Oxygenics shower head. Search this Forum for more info on Oxygenics.
Dick_B
2003 SunnyBrook 27FKS
2011 3/4 T Chevrolet Suburban
Equal-i-zer Hitch
One wife, two electric bikes (both Currie Tech Path+ models)