lookig at a 2004 a4 Q what is more reliable the 3.0 or the 1.8

Im looking at buynig a 2004 audi a4. Ive been doing alot of reading and have decided that the costs associated with running an audi are worth it. So heres the question...although im willing to accept maintenance costs i would really like to avoid a catastrophic engine failure. So what is more reliable and well built the 1.8T or the 3.0? I know the 1.8 has been in use for a long time and the 3.0 was only available in 2002, 2003, and 2004. ( i think. feel free to correct me). I love the idea of having an inline 6 but i need to know why the 3.0 had such a short life was it because there were many problems or did it just have to do with a horsepower race?