I really only keep my hands on the hoods when I bike, so I think I'm going to stick with STI's for now. I got a few pictures taken, and I appear to have a "Suntour Cyclone" front/rear derailer. The cassette does appear to have square heads. Can't find any more info on the cassette/freewheel, and to be honest know very little about them in general (I'm more of a computer guy myself ). How would I go about replacing them, what tools would I need? Can you link to some specific models of derailers, cassettes, and freewheels you guys would recommend? I get really confused on compatability, and Nashbar only has a few Shimano derailers all at $80+

As for the compressionless cable housing, the housing says "Shimano SIS SP 41" if that's any help!