Reliability of A4 over Model Years

[Einhorn Hofmann]

I'm currently shopping around the city for used audi options to replace my
current Audi 100.  I'm wondering if anyone could offer opinions on A4
models across the years.

There's an A4, 2001 for sale, Turbo quattro, 1.8L engine with 5 speed
tiptronic transmission for $3600.  The owner has spent close to $6000 on
repairs in the past two years.

I can also find an A4 2006 for sale, quattro, but no Turbo.  I'm looking
for more details but its listed for $4000.

I have to admit, I haven't followed Audi's beyond the 1980's to very early
90's.  They're so much simpler with less things to worry about, other than
the occasional unintended acceleration :-)

MC