it really depends on how experienced you are. some might say its a 4 or a 5. i would say its a -1 or 1. what you do is jack your car up in the back, and support with jackstands. place a pan under the transmission where the diff connects to it. there are 4 12mm 12pt bolts holding the driveshaft onto the diff. taking these bolts off requires a 12pt socket. make sure your transmission is in neutral and gradually undo the bolts while turning the driveshaft until all 4 are out. pull the driveshaft out and some fluid will drip out of the transmission into the pan you placed there. go get the other driveshaft and drip some ATF on the u-joint that goes inthe transmission. slide it in and turn it so the yellow paint splotch on the driveshaft lines up with the yellow splotch thats supposed to be somewhere on your diff. put the bolts back in and tighten, i would recommend using new bolts, they are cheap, like you can get all 4 for $5. i forget the torque spec right now, but someone will know it. also when you tighten the bolts snug them all up first and then torque them when they are all in.
Make sure when you do it to recheck the bolts after about a week. They may come loose, I have heard of many a person this has happened to including myself. You may want to put some loctite or any other brand thread lock on them to ensure they do not back off.