if you guys are paranoid about additives, Motul makes a nonsynthetic detergent-free and additive-free oil. Most people use it to break in a freshly built motor. There's this one video circulating around on the internet of a Civic that was drained of oil and coolant and it ran for about half an hour at full throttle. The only reason it stopped running was because the fuel line eventually melted and set the spark plug wires on fire. The spark plugs themselves were fine, though!
And for the record, if any of you guys pick up a BMW or feel the need to clean out the crud on the inside of your enigne, try some Mobil 1 Drive Clean. My friends use it on their cars when they put Japanese engines in. One of my friends put the stuff in, drove the car around for a few hours and it came out absolutely black.
I'm looking into E30s myself, but more of a fun daily driver car to supplement a potentially unreliable and expensive to operate car. By the way, can anybody point me out to a sticky or a site that explains all the E30 model year changes and the trim levels? (ie "325ie" "325iS")