Ok the reason I said about the front not as important is ask any one on here but one of the first things you should do to the mk4 is to add a rear ARB. This is why I was saying the front is not as important because I'd be looking to spendIng my money here first and see if that clears up the problem, and save the OP the bother of messing around with the front.
Also I looked at the OP post and saw that he had 1'8T so told him the S3 one because if Audi think its the right size for the S3 then it should be fine for him, yes i know they have a different hub wishbone set up so buying it would save him some money to buy the R32/TT/LCR/S3 wishbones and drop links. I never spoke about the size of the 2 sorry for not adding in there the same design but not size.
To OP if you go down this road and not buy the above hubs/wishbones you'll need spacers to get a ARB that goes below the shafts to fit to your standard wishbones pictures can be found on E38 of this and it looks all wrong.