My girlfriend pulled out the other morning after letting her car warm up and there was a huge 3ft circle where all the oil leaked out. I've been tracing a small oil leak for a while coming from driver's side, however I can't figure out where from. I checked the oil filter and it's on tight, and I also don't believe that I've left the oil filter gasket on after it's last oil change.

If anything it looks like the oil is coming from slightly ABOVE where the filter threads onto..maybe the oil filter housing?

You guys know of any culprits I can check? Common oil leaks? Lines?

 

Check where you stated and also the valve cover gasket for leaks. Its oil, so there has to be a trail

 

Oil cooler is right above the oil filter. It's fairly common for that to be a leaking point. Some need a new gasket, some need a new oil cooler.

buy parts from ECStuning.com, purems.com or autohausaz.com

 

i bet it's the half moon seal

 

wow...I'm surprised at how many of these are failing recently. It's the o-ring on the oil cooler. If you follow the link I gave you and scroll down a bit you will see a diagram of the oil cooler and oil filter. The part you will need to replace is number 6.

http://www.audiworld.com/tech/eng78.shtml