I did do this job a while back. It isn't too hard. Make sure the steering column is extended and the wheel is locked, then loosen the bolt on the coupling and slip the end out and push it back until you clear the seal. The hardest part is getting the new seal to mount on the lip of the firewall - use some grease on it and also on the other end. It landed up taking me about 2 hours working under the car and inside the cabin to get it right but now the car is quiet and I no longer have a draft of hot air on my leg when I drive
It is a dealer only part but as I recall it only cost about $12.