Many consider the supercharged model to be a "sleeper" due to its exceptional acceleration, despite its large size.

The supercharged models had the S suffix added to their designation to show supercharging.

When Bentley Motors refused to create the supercharged model, Birkin determined to develop it himself.

While the naturally aspirated 4 Litre was noted for its good reliability, the supercharged models were generally not.

The supercharged models, with the S suffix added to their designation, had superior performance at higher altitudes with a relatively small increase in dimensions and weight.

The Rk.17 was a 9-cylinder supercharged model, rated at 360 hp.

The Ion line will be spiced up next year with a 200-horsepower supercharged model.

Their Rk.12 was a 7-cylinder supercharged model, rated at 200 hp.

A supercharged model is likely to follow, along with other variations, possibly including a convertible.

The compression ratio for the supercharged model is 8.0:1.