it shouldn't be difficult to roughly work out how fast your car could go in theory rod if you know the power spread from a dyno session

we know that a 204 bhp std one will go 150mph (book figure, but the exact figure should be known) so you can work out the drag from that. you can also use other examples of sapphs doing top speed runs with known power amounts (like mike r?) to get an idea of the drag. then just multiply it up for your power figure

i thought you were an aero engineer