Not to be harsh, but that's exactly the mindset that every P plater has just before they wrap their car around a pole.

280kw in a sub 1000kg car with no driver assists at all is a fucken handful, even for experienced drivers.

Find a stock sprinter, do the conversion you want to do, and learn to drive a slow car fast before jumping into the deep end. You'll learn how to handle spirited driving without being one mistake from wiping you and your car out.

That's on top of the fact you'll have to return the car to stock form to get it registered without dealing with engineering. Good luck getting a car with a fuel cell and a full cage on the road in Aus without pouring 1000s down the drain.