i'm not comfortable with complaining about the racing curbs as it's often difficult to see exactly how cars interact with images. distance from the object, relative height in relation to the object can all distort perceived perspective. video and or close up pictures will be more telling, nothing better than first hand experience though
i do like the them and i think they will do very well in teaching corner lines to my kids who are currently smacking the corner rails often and or getting hung up with high angle rail collisions. they will essentially get a bit of buffer zone as they want to clear the turn close to the curb but still have room in case they cut it too sharp.
i agree the black rails look nice with the curbs and worm rails. thanks for the clarification though, turning into a black rail at some distance (like the pn/atomic tracks) would prove daunting indeed.