what material is the top (shiny part) of a tial wastegate made of ? fittings ?

[alesserfate]

The top part - it's aluminum isn't it ?

Is that round disk underneath it supposed to be a heatshield ?

There are two 10mm x 1.0 metric female's on top and on the side of the top aluminum part.

Considering this part will get relatively heated under extreme conditions, would aluminum fittings that will thread into the 10mm x 1.0 openings be good for use ?

I used the wastegate with steel banjo bolts and aluminum banjo's previously, but would like to get rid of the banjo in place for -AN.

I am asking this as I know you are not supposed to thread steel fittings into aluminum housings from previous experiences - where the steel expands more then aluminum when heated up and cracks the aluminum.

Input ? Aluminum fittings yes/no ?