I've done that change too... it's really quite easy and not dangerous at all if you follow a few precautions... here's a quick HOW TO guide...
1. Go to Dick Smith and buy a Torx tamper proof set
2. Ensure you have the radio codes for your radio. If not, get them from Holden (costs money).
3. Disconnect the car battery (completely, ie. positive and earth negative) and wait at least 15 secs for the power to drain out of the system. This disables your airbag system so it won't explode in your face.
4. Carefully undo the 4 screws on the back of the steering wheel with a T30 torx bit. Start at the bottom 2, then the top 2. Hold the airbag module before completely removing the last one to prevent it falling off the wheel.
5. Carefully remove the airbag module from the wheel and you will see two sets of wires attached to it. One with a red connector (horn) and one with a yellow connector (airbag).
6. Remove the horn connector (red) by getting a small screwdriver and inserting it under the tab. Don't try to push in the little catch from the inside part of the connector as it is solid. It took me a while to figure this out.
7. Remove the airbag connector (yellow) by simply grasping the connector and pulling it directly away from the airbag unit. It is a very tight fit so you might feel you are going to break it, but it's ok. Just remember to pull directly away (perpendicular to the cast aluminium chassis of the airbag unit). It took me a while to figure this out too! I almost took the yellow connector apart! Now the airbag module is free, store somewhere away from you with the front facing up.
8. Get a standard HEX Socket (17mm) to remove the centre wheel bolt. It is actually a reverse TORX bolt, but a 17mm fits quite snuggly around it and does the job perfectly. There is little if any risk of damaging the TORX bolt. Undo the bolt anticlockwise. It will be very tight, so hold the wheel whilst doing so, or get a friend to help.
9. Now before completely undoing the centre bolt, pull the wheel to get it loose (should be pretty loose already), then remove the centre bolt. Get a permanent marker to make markings on the centre spline shaft so you know where the centre is, and draw corresponding marks on the steering wheel so you know where they match up.
10. Remove steering wheel and replace with new wheel. Ensure that the wheel is straight. Check the marks on the old wheel, imagine them on the new wheel and mark sure they would line up with the marks on the spline shaft. Since the splines are reasonably big, it's kinda hard to stuff this up and put it on wonky.
11. Replace the centre TORX bolt and tighten up very tight, 40-50 Nm if you have a torque wrench. If you don't, just try to make it as tight as it was when you pulled it off.
12. Install connector plugs as you found them. Just press on the yellow plug, and insert the red plug until it clicks into place.
13. Replace airbag module and replace screws from rear of steering wheel. Be careful when you are putting the screws back in. Make sure you put them in at the right angle. If they won't go in, don't try to force them. If you damage the thread in the airbag module nuts (which are welded to the airbag module) then you would probably have to replace the whole module. SO BE CAREFUL!
14. Reconnect the battery.
15. Switch on car (outside of car just in case!!
), and check that airbag light on dashboard goes on, then goes off. This does a system check and if it disappears it means everything is A OK!
Basically this is it! If you are reasonably competent and have the right tools it will only take you about 20 minutes to fit. If you have trouble centering the wheel, dont' be tempted to drive around the block with the airbag module not on. This will register as a fault in the system or something like that.
Good luck!
