Great buy!! I wouldn't worry too much about the knocking noise, mine has been making a slight knocking noise for 200,000+ mi. that Beisan Systems says it's the vanos. They now offer a kit to rebuild them but I'm pushing 300,000 mi. now so I'm not going to bother with it. Still love this car but next summer I'll be replacing it.
I discovered I scream the same way whether I'm about to be eaten by a great white shark or if a piece of seaweed touches my foot.