i dono about auckland but AUTO BEND in chch are really good. you can make up the piping shape by using one fo these swimming pool noodle floaty things and a bit of wire in the middle and bend to shape,then they scan it or somethin and hey presto, custom piping, pretty cheap too.
surely there is someone in aucks that does somethin similar.
actually any engineer/fabricator will be able to make it for you take them a noodle bent to the correct shape.
most of the cost in getting pipeing made is the dicking around they have to do to get it to fit properly, not the actual welding and cutting as that takes no time at all, and the pipe is pretty cheap too.
or, if you have or have access to a welder just go to a exhaust shop get a few doughnuts a few 90s and 45sa bid of straight and have a crack yourself, thats what ill be doin should cost less that 100 buckas