Track rod head, crossbar bearing Omega B

Hello, have a good workshop that only performs the work I get the parts myself. But please don’t laugh at me *smooth* Only I’m a little confused because I came across different ones in the search for track rod heads. There are left outside and left inside. Are there on each side 2? According to the estimate of another workshop the track rod head must be renewed left outside. Isn’t it advisable to change both sides immediately? Then the crossbar bearings must be Vora chse left in the back and crossbar bearings front axle right in the back. Hää? Many I have a part number for the things? Why is there at ibahh 2 track rod heads for 16,- and on the cost advance is one with 56,- calculated? Thanks already on credit 🙂 Greetings, René