Hello I hope I’m right here and can be helped here. I got first registration from Grandpa the opel monza in early 83. With the 6 cylinder rows engine. Color whites it original condition with extras like the 255 rims original and other original accessories. The car now stood it 15 years the barn and has barely km down. It has to be done after the stand time some. Here now my own question. Opa is convinced that the car will increase it’s worth and I can’t find anything about whether he’s an investment. Can one more help me here. I hope very much.