Read: Fighting Techniques of a Panzergrenadier, 1941-1945: training, techniques, and weapons by Dr. Matthew Hughes and Dr. Chris Mann, 2000, 0760309310.
An interesting book. Hughs and Mann cover the Panzergrenadier from conception through the end of the war. Panzergrenadiers, like most things German, changed over the course of the war. Units were split apart or reassigned. Older units were newly designated as Panzergrenadiers. Vehicles were broken down and not replaced. The Eastern Front ground everything to the nubs.
Panzergrenadiers were revolutionary because they were the first mobile infantry. The Panzergrenadiers were an integral part of tank warfare. They were given plenty of vehicles so they could keep up with German tanks. Panzergrenadiers could protect the tanks and clean up resistance pockets the tanks bypassed. The concept of armored personnel carriers began with German halftracks (the Krauts used two basic types with several variations) that were lightly armored but able to get within a couple hundred yards of the fighting for the infantry to debus.
Panzergrenadiers were favored units, often SS units, and got all the best and newest equipment. They were also elite units with extensive training. The Hitler Youth Panzergrenadiers in Normandy were trained under very realistic situations (there was an acceptable death rate during training) and proved very stout opponents in the hedgerows. During retreat from the Russians the Panzergrenadiers acted as shock troops for trouble spots. Halftracks would have to be used as assault vehicles when no tanks were available. When industrial production was crippled at the end of the war the Panzergrenadiers had to walk but were still strong units.
Damn, dirty, filfthy, rotten Nazis.
Guy Sajer, whose memoir Forgotten Soldier I read a few years ago, was in a famous Panzergrenadier division, Grossdeutschland.