The main thing to keep in mind when replacing an alternator on a Mercedes m112 or m113 is to pull the brass guides (where the e-torx bolts go through) back out towards the front of the car. This can be done by fabricating a puller with a longer bolt, a nut, some washers and an 18mm shallow socket, or by VERY carefully using a large set of channel lock pliers to press back the guides. They only need to move maybe 1/8". If you try and force the alternator back in without doing this, you could potentially damage the alternator support bracket (which is the front cover of the engine). Overall an alternator and a battery is a pretty simple task. You'll need a 17mm for the belt tensioner (to remove the belt, I believe an E12 for the alternator supports, a 12 or 13mm for the b+ on the back of the alternator, a 13mm for the battery hold down and a 10mm for the + and - terminals. Also, a small pry bar to get the alternator out once the bolts have been removed. If you're getting bearing noise, both of the idler pulleys are easy to replace and are likely the culprits. When replacing them, absolutely do not overtorque. Get a torque wrench. I believe the spec is 25nm.