I have a 2004 Honda Civic DX/LX; I'm looking at a few Eighth Generation Civics at a local junkyard to swap transmission -- are they compatible with my vehicle and how can I find out? (I'm also looking at a couple of Seventh Generations that aren't in as good condition as the others.)

 

Your civic is running D-series engine and the eight gen civics are running R-series and K-series engine. The transmission from the eight gen would not bolt on to your D-series.