what kind of pickups and what are you trying to accomplish but changing them? Are you going to a hotter pickup? how many connections are there on the new P/U? If you wire them wrong they will sound like ASS!!! If the coils are setup for coil tapping and you reverse the current, you can make a Les Paul sound like a sitar.
I specialize in this, sorry to freak you out.
And yes, if they are active and you are putting in a preamp or are going to a double coil from single and require routing, have a shop do it. It is entirely too easy to render your guitar unusable if you start routing.
So, what do you got?
me