The focus is all on the exhaust in this update. I started by applying putty on the inside.
Partly do fill in the seams and partly to build up where needed. It took some passes with sanding inbetween. Here I’m still not done.

Once that was done I started painting the inside. Trying to replicate the patterns and general look inside.

The inside on the “bottom” part also got some paint.

I might need to redo some or simply glaze with some more insignia white.
I guess I can just mask the outer most part while painting the outside. Possibly I have to wait until I have put the exhaust pipe in place to make sure it sits nicely, before painting.