Ours are mild steel,made out of a regular Hedman header kit. Except the flanges, they are self made out of 1/2" flat and common flange, milled flat after welding. No Gaskets, just RTV, no problems whatsoever. My plan was to keep the primaries smallish and short and since the turbos have devided flange it required some routing to keep the pulses as far of each other as possible. After ready they were ceramic coated, and they are supported to teh frame from the flanges. Don't have very good pics, but here is a couple: