Why FD?

As you all know, the standard GPL has three types of cars. GP (aka F1) Advanced Trainer (aka F2) Novice Trainer (aka F3)
These all cars look identical from the outside, and in fact (from what I understand) they only differ in two things: Engine size and amount of Grip. (I the weight of each car chassis may have been "tweaked" to create the other two classes. As an aside, Papyrus had intended to create completely new cars for the Novice and Advanced trainers, but ran out of time - They resorted to simply modifying the "technical parameters" of these, and kept the rest the same as the GP cars) What really sets the these classes apart is the type of driving they require to go fast. Whereas with the GP cars you can afford to stand on the brakes and use the excess (ive) power to make up for it on acceleration, F2 and F3 cars are much less forgiving to non ideal lines and heavy braking through corners, as they require so much more time to accelerate. The other "quality" of the trainers is that they don't have nearly as much grip, and coming in too hot into a corner can lead to gray hairs...
Enter the Engine Manager
A little while back, someone found out how to hack the GPL exe to put any engine into any chassis. This knowledge was used by Paul Thurston to create a nifty little application which allows you to do this with ease. Paul's reasoning was that if everybody new and was able to do this, then people wouldn't use this knowledge to try and cheat. Though this was a contentious issue at the time, I believe that by now, Paul's idea has been vindicated.
So what does this engine swapper actually allow us to do? You can assign any engine to any chassis, like thus:
Any GP chassis with any GP engine.	ie. Brabham chassis - Honda engine : Lightest Chassis with most powerful engine = loads of fun in the corners :-)
All F2 chassis with any engine	If you dare you could put the Honda GP engine into an F2 and see if you can keep it on the track...
All F3 Chassis with any engine	If you are really looking for trouble you could put said Honda engine into one and see what happens... ( anyone for skating? )
What we can also do is add the F2 engine to a GP car. This is what we call FD. The great thing about FD is that we get the extra grip from the GP chassis, but the power of an F2 engine. This results in cars which, though still very close in performance, are easier and more forgiving to drive than standard F2. This is ideal for close, fun, online racing. So go patch your GPL and come out and play!

An introduction to FD cars