Well....i do not suggest 18's in the first place. They will make your mkII slower and they tend to make the front end look really high. I recently upgraded from 15's to 17x7 and 17x8's on my mkII. As for tires, it depends on what you want. The general consensus for the front is 215/40/17. As for the rear, 235/35/17 or 235/40/17 will work fine. I have 235/40/17 which fit quite nicely without having to roll the fenders. But the rear is a toss up, i've heard/seen countelss tire sizes for the rear. Hope this helps bro.