Like adsm08 said, 12 point wrench is what is necessary. You might also add a little heat, such as a small propane torch to the list. Sometimes those four bolts are stubborn because of the loctite that the factory puts on and the years of rust, the heat helps to break it loose.
I've also always marked the driveshaft so I put it on in the same orientation as when I removed it. Although, the last time I removed it, to do a clutch job, I forgot to line up the marks and just slapped it on there. No additional vibration has been noticed but I may have just been lucky and put it on in the same as it was removed...