ford econoline v8 conversion euro2

Hello I urgently need your help. I bought a Ford Econoline Van Bj. 87,the predecessor brought him from the states as a souvenir,a nice guy. I was aware of the tax problem.The consideration of taxing the van as a special car would be a possibility.Construction measures I wanted to spare myself from the original. Since I often also stay in Berlin, I wanted to upgrade to Euro2, Well my call for help, I can’t find a cat for this model. Can someone give me a tip where I get this thing or what alternatives are there???