With sport models the size intake isn't a big deal if it's large enough.

With speed models the size does matter for two reasons. Those reasons take on the same importance as your desire for the ultimate top speed is important.

One of the two is that if the intake is too small your engine is going to run hot. Who'd'a thunk it.
The other is if it's too large your engine might actually run too cool for best performance and the airplane won't be as fast as it could be because of the too big hole.