Oogling the boom engine made by futch and from the box, sold thru ihysc roboterkampf... It's really detailed and made of 3 parts and a piece of wire which replicates the pipes.
I had initially thought I could scratch build it using pictures from the Mak books but after seeing this resin, there is no way I can get to this.
Also dropped the idea of rubber casting to make a duplicate for the other side cos it's too complex a shape.
Going back to the build, I added plapate to the air brakes, putty up the gaps, and added another thinner layer to simulate the front bulge being slightly thicker and being bolted on.(see the one on the back)
In parallel, I am scratch building another main weapon based on Zuru jp's sketch of a Falke mounted on a tank. I sketched it out on a piece of paper and will build it based on a lighter. Note that I dun smoke, lighters are used for lighting candles on birthday cakes.