Has anyone ever had a custom exhaust manifold made?

[Poodle]

There's plenty of room to play with once the turbo is moved out of the way. We'll be looking into making up a larger log mani in the next year or so, a proper equal-length runner 4-1 mani is going to cost a lot more for not much gain. If you're making it yourself I'd suggest a minimum of 8mm steel for flanges you'll be welding on, get reasonable quality steel too as the cheaper stuff warps more when you weld it.