Is the type of material critical for the down pipe?

I see steel , galvanised and stainless steel.

Any comments on choice of material?

Would a fiberglass heat wrap help?

 

Sorry I got lost for so long, snow duties were calling me.

Thanks for the info though, sounds easy enough.

After swapping several IDI motors, I noticed every one of them sat in the truck a little different.
So since everything except the block was the same, the differences appeared to be in the block motor mount hole locations.
The difference was very noticable with the ATS turbo and 3" downpipe I am running on it.

Am I understanding correctly that the Tymar down pipe is 3" up top and 4" down below?
If that is correct, that sounds like the one I want if the transition is nice and long.