The 2 tow brackets are mandatory for particitation in the 4L Trophy and the round thing is special tool B.Vi.494 used for loosen or fasten the differential nuts and adjusting the differential play adjustment. But it could easily be a sort of timing disc for a monopoint injection engine
The towing bracket at the front wil sit on the left side under the bumper mount bar. When I put the gearbox back into the Sinpar Ill place the to towing brackets to.