temp. and fan speeds

I have an 1990 audi V8 quattro(3.6), for the past 12 month nobody seems to be able to answer my question and or solve the problem!

At what temprature is my car suppose to run?

When I bought the car I noticed that driving it on the highway it always kept a steady temp. between 80 and 90 degrees but in congested city driving it would rise to 110 maybe even slightly above without ever boiling over. After having at various shops the radiator flushed, the fan clutch replaced, the thermostat replaced and finally at the audi dealership in Calgary,Alberta-Canada I was told that this is normal for my car I have run out of options!

It is hard for me to believe that a V8 is suppose to be operating at such high temp. I am afraid I am doing engine damage at these temp. but nobody seems to be able to solve my problem, is it a problem or is that normal for this car?

I bought the car in New Hampshire, does some kind of corrosion cause this?

I looked in the owners manual and as far as I can tell their seems to be 4 different fan speeds but if I leave my car idling for a while it always runs at one low fan speed without ever going up in different speeds and the temp. goes up.

Can you help me on my search?