Exhaust sizing appear to be far too restrictive.

[PhillipM]

It does fit on something else yes. But you'd find most race cars where the headers aren't restricted are far longer than the OEM ones. To the point where the cat converter is removed just in order to get the right length in.

That picture on the previous page is ITB's on a stock engine. You design the ITB's to suit the engine, not the other way around

[darkjedi]

no, no , I meant an engine designed to use ITBs , not around the ITBs. different sensors, different ports, etc.

[PhillipM]

What different sensors and ports? You don't need anything any different from the normal engine. It's just a manifold at the end of the day, that happens to have some throttles in it.
Anyway, it's not game breaking, just a niggle.

The exhaust potentially is though as high power cars are going to require absolutely massive exhausts to be fitted into the car body somewhere later on in the development. It'll also stop people replicating stock cars.