A previous discussion included a statement about crossover components.

The commentator stated something to the effect that some very high end speakers really cheaped out on the capacitors and resistors in their crossovers, and hinted that replacing them with high quality components might improve the sound quality of the speakers. My question is "Have you ever replaced the caps and resistors in your speakers crossovers, and to your ears did that result in better sound quality?" Also, what brands of caps and resistors do you consider to be "the best", and why?