some pros are pretty superstitious about gear.
a girl I know on the tour (career high around 70ish in singles, and 30 in doubles) used to play with the nTour and the kTour, but could no longer play with a racket with an assymetic paintjob, so she is no playing with a Steam (which is 0.25 inches shorter and 5in larger).
she used to use both sides of the strings to hit the ball, but because of the kTour's paintjob, she now only hits the ball with 1 side of his strings.
she never lets the stringers stencil her rackets, because the W needs to point the same way all the time.
...meanwhile, her rackets are pretty much stock (not much lead if any, lux mains, gut crosses strung lower 50s)