I received my comm replacement and fussy brushes last week.
Replacing a worn comm was soo easy
It took me 1 hour the first time because I doublechecked every step against the instructions. The 2nd comm only took about half an hour.
Getting the solder out between the comm slots is a bitch and if you don't do that properly you will short the arm and it will overheat and blow up.
(Put it in a can and spin it, if it doesn't spin freely it's still shorted)
On the Robitronics dyno I did not notice a performace decrease, I did notice the comm got larger though in the graphs.
Next Sunday I am going to see if the comm sleeves hold up.
(Going to try a 12x2 and an 11x3, not really spectacular winds but that is what we run mostly due to the 12T rule in Europe)
Also I am very impressed with the service I received from Dewayne Harlow.