So when I took out my intake manifold I noticed some oily build -up on all the surfaces. Should I clean it or does it really matter? If it should be cleaned, any recommendations on what to use?

 

Get a can of seafoam and run it through the vacuum line on the intake side and then run the other half of the can through the brake booster line and that should clean up most of the oil. Once it's all clean, look into getting a catch can from needswings and it should stop the oil build up.