Cone air filter and custom heatshield
Ellipsoid headlight install: High/Low beam issue
Blacking out the grill kidneys
Dynomax Superturbo sounds
Cleaning the ICV (Idle Control Valve)

Other Links:
E30Sport.Net - Dedicated to the E30 BMW. Great forum and good articles.
DTMPower.Net - BMW enthusiast site. Good forums and videos.
MaxBimmer - Videos !
BP's E30 318is Site - A great resource for the E30 318is.
Unofficial BMW - Good forums which provide some technical advice, instead of info on how you can fit dubs on an E30.