Trinity XXX brushes I wouldnt even compare POWER wise to Reedy 767's,F brushes and Putnam Green's.
Not even in the same category.
So dont pay $8.00 cost,$13.00 selling price for a brush that while it last a LONG time is hard on comms and simply doesnt give the same performance.
Tuning a motor like he says is found all over the Net.
Simply do a search on "Stock Motor Tuning for R/C"
Hope you have a good time and hope you find what you need.
Les