My 2001 Olds Intrigue came with crappy cloth seats (ugly color, bad quality material), so I want to find a leather set to swap in. The carpeting is tan, so I'll probably try to find some tan leather seats. My question is, would leather seats from a Grand Prix (or other W-body'*) bolt directly in?

Yeah, other W body seats should fit. Be careful of GP seats. I find them to be very uncomfy.

Some models of Intrigue can have leather and heated seats.

Yeah...I miss my Bonneville seats. They were the early-90'* SSEi ones with the 10-million-way adjustable air bags in them.

I'll try looking into getting the heated leather ones. : /

How hard would it be to run the wiring for the heating element(*) and mounting a switch?

It'* very easy.

If the wiring isn't already under the carpet (many times it is) it'* not too bad

Hmm. This just occurred to me, after seeing a picture of the higher-end model (GLS)..

It came with a digital climate control system, which is the same size as my analog one. How difficult would it be to swap out my analog system in exchange for the digital? Or does the digital have an entirely different harness? (As I suspect)

Hahaha..never mind. I just did a bit of searching, and it sounds like a lot more trouble than it'* worth.