I agree with the above, and would just add that if your pickup lacks highs (i.e., is a high-output unit), there's no way you're going to add them later, whereas a low-output pickup can easily be made dirty with the right amp and proper adjustments. My favorite combination (of humbuckers) is a Seymour Duncan Jazz at the neck and a Dimarzio Virtual PAF at the bridge. You'll get wonderful chimey cleans, and nice articulate distortion when overdriven with an amp.
Joe
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