If you find it hard to get into 5th this could be an alignment problem, or the small link rod in the engine bay with the plastic end pieces is broken, the one in my 1.6 Driver had a hairline crack in it which made it very difficult to select 5th. Also if you can slip into reverse without pressing down the stick it can be the reverse gate stop like gambit says or the gearstick housing under the car has worn, I had this both on my 1.6 Driver and my 8v GTI.
The gearlever housing is pretty straightforward to do but a bit fiddly, idealy you need a mate to help you! You can still get the repair kit from VW, part number is 191 798 116A. I would recommend you get the genuine kit, this isn't a job you want to be doing twice!.
1. Remove the gearstick gaitor & centre console to give you more room to work
2. Undo the 2 10mm nuts either side of the gearstick.
Now get under the car
3. Remove the exhaust centre heat shield by removing the 6 nuts/clips holding it on, then rotate it round the exhaust an off the car
4. Shove the housing up into the car, it is only held in by gravity & grease at this point
5. Remove 4 13mm nuts holding the plate
6. Now get back in the car, pull up on the stick and push down on the plate you have just undone
7. Next Jiggle the housing about untill you can get it out
8. If the ball looks like it is worn you can remove it, I didn't bother as it looked OK. Its tricky, you need to press the ball upwards while someone holds the gearlever down, then you need to remove the split pin. Not an easy task!
9. Refitting is the reverse of removal
