You only have to worry about the driveshaft if you seperate the front and rear sections. You will not have vibation problems just installing the flex disc in any of the positions that it wil bolt in. The allen bolts in the diff are 12mm. There is not very much space between the tank and the bolts. I typically use a 12mm wrench on the allen bit b/c the ratchet wont fit. Be prepared for a fight the bolts are fairly tight and are loctited too. Expect to use a cheater bar on whatever you use to turn the bolts. The front diff mount is an 8mm allen with a 17mm nut on top that can be difficult to counter hold. A shorty 17mm wrench is priceless there. With the diff out of the way the bushings are a press fit. An air hammer removes them pretty effectively. I always use the MB tool to press them in but a bolt and large washers can get the job done in a pinch.