I did this swap on my '86, but I don't think it would be much different on a '91. You need the complete tilt column, turn/wiper switch, and the plastic cowling for the tilt column. On the '86, the ignition switch wiring is part of the column loom/connector (IIRC), so you will either need to get a key with your used shaft, have the new switch rekeyed for your existing key, or have a new key made to go with the new switch.

It's a very straightforward unbolt/rebolt. The only tricky part is keeping the new wheel centered and making a good mate from the new steering column to the steering gear box, as the U-joint wants to flop around, and you're on the other side of the firewall flying blind as you try to land the U-joint on the splined end of the gear box. I needed a second person for this part of it, but the rest was cake.