my friend had a 98 A4 1.8T, but it wasn't a quattro. I drove it at times as well. seemed fine. he didn't have any major problems till 110K. He was the second owner and bought it at around 70K. All I can say is, compared to my w124, his A4 seemed to be 'trouble free'
Whether you think you can or cannot, Either way you're right!. by Henry Ford.