Not that hard.

Take all of your carpeting out. Remove the plastic clip at the bottom of the accel. pedal. (you might prefer to "sit" upside down on your seat) There is a clip that holds the cable in place...remove it.
Go back outside (let blood drain from your head) and disconnect the cable at the linkage. You will see its just a matter of compressing and squeezing parts to get them out of their spots.
Push the cable through the first firewall (the one between the fuses and the engine). From there, I pulled on the cable, and after a reasonable tug, it came out.
Stick the new cable down the hole (the hole, although partially obscured by plastic lines, is "find-able")
I think that a good tug, got the end of the cable (it has "barbs" on it) got it back into its home.
On the top side, thread it back through the hole in the firewall, and connect them appropriately - save the fine-tuning for when you have the other end connected.
Once you're upside down again, replace the clip that holds the cable in place, and put the clip for the pedal base back on. (don't put the carpet back yet)
After your head has drained again, you can play with the adjustments -top side, and inside, so that you can get rid of any slop, and have instant response.

I know.. I know.. I should've taken pictures.

If my directions seem a little odd to understand, just get yourself underneath there, and take a gander...it's all pretty straight forward.

Good luck!

-Larry

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D