There are 2 sizes of end cap, just measure the one you have currently and order that size. 79mm and 84mm iirc.
Don't know what you mean by shim. If you mean shaft play shim kit, you don't need it on an 08 car. Only 04-06 cars need that.
Use the G 052 171 A2 stuff. Yes its expensive but its much better than cheaper alternatives.