It's kind of weird the US trucks have exhaust clearance issues. The RHD trucks have the steering box over on the exhaust side of the engine - not a lot of room over there. So...theoretically you could use the headers off the Starwagons but would need to lengthen the second section pipes to gain floor clearance. A bit of grinding and 2 straight lengths of header pipe welded in and you'd be set to go. It wouldn't even alter the collector geometry which means no messing with jigs or bending.