advice on buying an A4

hey,

looking for some tips on things i should be aware of. i'm (possibly) going
from an '85 Jeep CJ7 to a 97/98 A4, so any advice is a welcome bridge across
the performance/construction/purpose knowledge gap

general questions:
any known mechanical issues?
avg fuel economy?
options to stay away from?

more to the point, i've found one that seems to fit my bill for
price/year/yada,yada:
"97 A4 1.8T QUATTRO, bucket seats, heated seats, a/c, AM/FM stereo, CD
player, power everything,
upgraded turbo, suspension, muffler system... $8000 obo(CDN)"

now i know as soon as i see "upgraded" i'm gonna want to see reciepts of who
it was installed by and when, but does this sound like an alright deal?
doesn't appear to be any body damage and not sure how many km's on it, but
that can factored in when/if i go look at it

thanks again,
looking fwd to getting my own A4 to tear into!

adam