2001 Audi a4 2.8 quattro or 1.8 turbo quattro?
 

Which has more power stock?
Which is more reliable?
Which has better resale?

2.8 gets the best of everything on what your looking for the 1.8t is slow breaks easily and the 2.8 just runs and runs comes stock with the nicer leather seats =]

These are the simple shortened answers. There's loopholes and such, but this is generally speaking.

More power stock - 2.8

More reliable - 2.8

Better resale - Toss up, I'm not too sure if one has a better resale than the other to be honest.

2.8 does cause the v6 is so much better than a 4 banger and a 4 banger engine with a turbo is bad news alot more issue's

The search button has more power and better resale value

check out this link! I hope this is everything you were looking for dude
http://lmgtfy.com/?q=b5+audi+a4+powe...%2C+and+resale

lol click the first link and watch that video... well heres a link to it so funny... all riced out most of them

http://www.youtube.com/watch?v=KkNkQRC0czc

the 1.8t is easy as fuck to work on.
chip the 1.8t, its faster than a 2.8 even if the 2.8 is chipped. and no it does not affect the reliablity of it.
2.8 or 1.8, both will need repairs. I have had minimal issues with mine even after installing my bt. most repairs have been genral mtce issues like timing belt and brakes.
it all really comes down to what you want the car to be. the 1.8t has more tuning abilty to it. if you search, you will see that most ppl would agree that the 1.8t is a much better platform to buy.

^ +1 they will both cost you an arm and leg. at least a 1.8t has potential

Everyone says the 1.8t is less reliable, but not sure why. Haven't seen any problems with the 1.8 that don't occur with the 2.8. Get the 1.8 and chip it and you be thankfull you didn't get the 2.8 :)