The air filter is located beneath the fuel distributor, behind the battery. There's four clips around the air box that you need to pop off. Once this is done, you should be able to open the air box with the fuel distributor, fuel lines, etc. still attached and pull the filter out. Honestly, this is 100% easier if you just move the battery out of the way first, but it's not necessary.
how to change a 2009 VW Jetta Air Filter and location
To replace the air filter on a 2007 VW Rabbit, you need to remove the screws holding the air duct, then gently push each end of the plastic engine cover and pull it off, rotating the unit to the side before removing several more screws to gain access to the filter. If you want to know where the filter is, there is a diagram in the engine compartment.
To change the air filter on the 2002 VW Beetle, just remove the air breather cover by unscrewing the center nut. Then, remove the filter and add the new filter in its place. Place the cover back over the filter and replace the nut.
Remove the passenger side kick plate in your 2004 VW Jetta. Remove the cabin air filter container cover. Lift the air filter out and drop in the new cabin air filter.
There is no 1991 VW Rabbit.
Usually it is just spring clamps you just lift up (4 of them) and then lift off the plastic cover, then lift out the filter and replace with new and snap down the clips.
Remove the top to the air filter housing. The air filter housing can be found in the engine compartment. The air filter will easily lift out. Put the new air filter in.
Very carefully :)
There is an article here on how to change an air filter ; http://www.carbasics.co.uk/how_to_change_air_filter.htm
http://www.tobio.info/passat/howtos/passat_air_filter.html
Check this link, there is a pictorial of how to change the factory air filter on your VW 2.0T FSI motor. Hint, it takes patience, strength, finesse, and a lot of cussing. http://forums.vwvortex.com/zerothread?id=2547554
http://www.tobio.info/passat/howtos/passat_air_filter.html