This header is to suit a FG 5.4 lt boss V8. The headers will fit the XR8 GS and GT, they are manufactured from mild steel and are supplied with ceramic cats. The headers are a 4 into 1 tuned length design with 1 3/4 primarys. This header will give a great sound that others will admire. The X force system is a proven performer on the dyno and race track. Pic is of stainless steel version. 00071804