I put heaters in the seats I put in my Grand Prix. Only took me a couple hours. I would recommend buying some hog ring pliers; it'll make your like MUCH easier. Lucky for me GM used crap hog rings, and very few of them at that; they just crumbled when I tried to open them. The covers on those didn't really need them anyhow. Once you get the covers off, you just use the provided tape to attach the elements to the covers, run the wires out to the bottom of the seat, and put everything back together. Wire it up (I did mine off constant power, not a good idea in hindsight; use a relay if not provided and run the trigger off keyed power) and enjoy a warm tush on those cold mornings!
No idea how the coolers would work though.