Hey everyone. new guy in need of some help thx!

Hey everyone..well i'm new here and mainly signed up for the beauty of the audis..the s4 has me daydreaming..and i came across a deal that i'm a bit unsure of taking but am awfully tempted..

It's a 2002 s4 the car was in an accident airbags didn't deploy and i can't really tell what kind of damage it has besides the pics..the guy is asking for cash or trades..and i just want to make sure that i don't get jacked..

So i currently have a 2001 ford taurus ses it's got 86k and with everything in it i'm planning on selling it for $5500 but i saw this guy and like i mentioned he wants cash or trade. he's looking for $6900 obo. now with the car being salvage and the pictures that i'm going to show you. i need your guyses input on what i should do. the s4 has 80k or probably more likely around 81. is there anything that i should be concerned with if i take a look at it? please let me know i really really appreciate it since i would to totally love to own one of these beauties