I've has this happen a few times in the past, one guy even showed up 3 days later (after scheduled time) to buy an item un-announced, WTF?? Told him to fcuk off, didn't go down well..........
By saying 55 wagon I'm assuming you mean a ke38? If so, yes it will be a BorgWarner diff. Yes the BorgWarner will bolt straight in, only other thing I would grab from the wagon is the tail shaft, then just swap the diff and tail shaft over and your good to go,
cheers!
Filfred is right, much cheaper to just get another shell, I have had a complete roof replace on one of my rolla's, chopped off through the pillars, and the car needs to be braced to the shithouse to avoid distortion,
cheers!
My suggestion would be to check your float level on your carb if the bowl is too full, and by your video I'm assuming you have a vacuum leak which could be causing your car not to idle,
cheers!