first of all, yes i searched, but didn't find good answers.

i've got most of the parts for my turbo setup already, but i'm uncertain about my downpipe situation. for charge piping i'm just getting a friend to bend me some 2.5" aluminzed steel (not mandrel, but not crimp either, i think it reduces the diameter just a bit).

so would the aluminized be ok for the dp and dumptube as well, or is it necessary to use stainless? would his non-mandrel bends be ok for the 3" dp and exhaust?

 

Alumized non-mandrel bent piping should be ok, BUT it would be better to use mandrel bends to improve flow

 

any particular gauge of steel i need? the thicker the better i guess for the dp right?

 

16 gauge should be good