Thought I would chime in as I have gone through this scenario with my 2002 Pathfinder.
Bear with me on this.
It came originally with cloth seats, manual adjustments, and not heated. I wanted an upgrade as well.
I pulled an entire black leather interior from an '01 wrecker, and installed it in my truck last year.
The good news is that the seats bolted in no problem.
The bolt fitment is the same from '96 through '04. All the seats from any R50 will bolt in no problem.
The bad news is the electrics.
The "new" leather drivers seat I got had a different (extra) plug and cable for the power seat functions and heat.
The seat belt sensor was the same, but the rest was different.
My truck did not have the necessary harnesses under the seat.
Therefore the power seat portion did not work. Fortunately, the seat position that it was left in was good for me.
(Not so good if a shorter person ever drove it.)
The heat function is also not operable.
The passenger seat was a different matter. It plugged in no problem, and the power functions worked.
I never got around to trying to get the heaters to work though. I did install the switches in the centre console, but there is no heat.
Now, here's the interesting part and something to be aware of: The leather seats come with air bags. The cloth seats don't.
In my enthusiasm to try and get my drivers seat to function, fooling around with the harnesses and wiring, I accidentally powered up the air bag, and it exploded 12" from my head (I told this story in an earlier thread). The seat is now ruined, and sitting in my garage. I re-installed my cloth seat in the meantime.
Now here's my update:
I went back to the wrecking yard today, and found a 2000 Pathfinder with a leather interior.
I took the whole interior, entire front and back seats ($50.00 all in. excellent deal).
Turns out the 2000 seat and wiring is different than the 2001 I picked last year.
I just finished installing the drivers seat this afternoon, and it had the proper connectors that mated up with my existing harness. Go figure.
The power seat from the wrecker 2000 Pathy works in my 2002. I have full adjustments available. It works. No seized motors or anything.
I'm pretty exited about it.
Weird that the 2001 seats don't fit (electrically), but the 2000 seats do.
My next job will be to get the heaters working.
I still have to replace the other seats. The ones I picked last year are black. The ones I picked today are grey.
I actually prefer the grey, so I'm pretty stoked.
I'll be working on all of that tomorrow.