[font=trebuchet ms]I wanted to check this out with my guitar tech before I answered.

General rule: higher volume pot resistance = more top end frequencies.

The upper limit on this seems to be about 1 Megohm. A 1 Meg pot will turn a Tele into an audio ice-pick. 500 k Ohms is fairly bright-sounding. 250 k Ohms is a bit darker.

Note that the Tone pot is a different consideration, because it is the coombination of this pot and the capacitor that determines how much treble is rolled off.

So, if I changed the 500 k Volume pots in my Yamaha SBG1000 to 250 k, it would reduce some of the high-frequency harmonics and overtones. If you find that your pickups lack detail, or sound a bit dark, it may be that changing the volume pot to a higher resistance would solve that for you. It would certainly be cheaper to try that than buying another pickup.[/font]