Did you know Skylines have Active Aero?

Active Aero is a system seen in many new supercars and sports cars that are desperately trying to claw their way into the supercar segment (Ahem Porsche).
The way it works is that when the car reaches a certain speed, the wing at the rear will rise and/or change angle to aid in downforce and change the aerodynamics of the vehicle for stability.
In some cases a front spoiler or splitter comes out from hiding to see the world fly past at 100miles an hour - this is how it works in Skylines.

R31 Skyline

The first Skyline to feature Active Aero was the R31. It wasn’t available in the GTS-R (the predecessor to the R32 GT-R), but it was an option found in most GTS-X Turbo models, and may be found in other models such as the GTS.

Only the front lip is movable and it extends once the driver exceeds 60Kph, or it can be controlled by a switch to the right of the steering wheel, unlike the Mitsubishi 3000GT where it only comes out when traveling at speed.
Once the button is pressed, the lip flips out electronically from under the car.

R32 GTS-t M-Spec and GTS4

While it was very common to find an R31 with a movable front lip, less common is the aero lip found in the R32. It is only available in turbo models, excluding the GT-R, and can be controlled by a switch located to the left the steering wheel, below the gear-display on automatic models (where the clock is on GT-R’s). When pressed, the splitter extends down from behind the bumper.

Unfortunately it is unwanted among tuners since it gets in the way of a front-mount intercooler should the owner decide they need one. It is also a common misconception that they break easily and must be taken out before they break - being Japanese electronics from the late 80’s.
I have seen many R32’s where the owner has removed the electric motor and re-attached the splitter for the look - even one that was painted bright pink.
Finding active aero on an R32 is more common than finding the leather seat package, which is quite rare.

R33 Type M

Very little is known about the Aero wing found in the R33 - the only ones I could find are from a series 1 Type M, and the model below found on GTR.co.uk.
Like the R32, it is hidden under the bumper and extends downwards electrically when the button is pressed, or when the vehicle is traveling at speed.
This is a very rare option on R33’s, and I have not seen a facelift model with it.

The buttons for the R33 is located between the steering wheel and the stereo - in a slot usually reserved for the switch to raise/lower the radio antenna.
Like the R32, it is often removed from the R33 in order to fit an aftermarket bumper or intercooler, meaning this is extremely rare.

As for the R34, there is no mention of it in any brochures so I would assume that, due to the low volume of R33’s ordered with the active splitter, it had been cancelled in favour of a Nismo aero package.