I have an 04 Rabbit Gti (which is incredibly hard to find info on!) and today driving home from work the engine light came on and was flashing. Along with shaking and really rough idle and it's not accelerating right. Lucky enough I have to get up to the dealer today but I just wanna know what I might be looking at and if it'll be ok driving up there?

If the check engine light came on and is flashing I wouldn't recommend driving it. It's probably a bad coilpack and you're getting misfires from it.
What exactly is a coilpack?

Part of the ignition system that converts a low voltage from the battery into a high voltage giving the spark plug the required energy to ignite fuel.
Here is a TSB that might apply to you.
http://www.automd.com/tsb/bulletin_b298707/
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