Oh one thing I forgot to mention..
Before this 50kph value becomes some sort of fact I think it is important to point out that the data is from a 109G and we are talking about the in game 109E! And I am pretty sure the radiators changes a lot between the E and G model.
And don't forget what Hatch pointed out! That the data is from a non standard radiator test!
What does that means?
Well maybe it means a standard radiator only causes a 25kph (or less) difference, or maybe it means a standard radiator will cause a 75kph (or more) difference. We don't know.
But I think we can all agree that radiators will have 'some' affect on speed, how much we really don't know.
We can agree to disagree as to if someone can 'see' a speed difference of 50kph or less!
But here is what we know to be true
Some people do 'see' a speed difference and others do NOT 'see' a speed difference
How do we decide who is right?
I know how and it does not require a burger king campaign on picking between a werewolf or vampire!