What parts do i need to change on my 1.4 mark 3 VW golf to change it from four to five stud hub like a GTI?
Answers:
you've pretty much answered your own question!
you'll need to do a little research to detemine whether the suspension leg to hub mounts are the same size on both models- easiest to do this at a vw breaker.
the drive flange (which has the five holes) is the main requirement, but the wheel bearings could well be bigger on a GTi so you may need the entire hub and outer cv joint. cv's are normally interchangeable between different models/driveshafts so should be a simple swap. although im guessing you want to do this to fit different wheels, it also opens up the possibility of upgrading your brakes too.
if you buy the job lot off a GTi it would be advisable to change the wheel bearings while its stripped down.
hope this helps