The engine can't fit in a RS or GS without some heavy modifying. This may have been answered already but I'll chime in. Like Miguel stated the Evo 8 motor would be a good swap but I've only see it in pictures in a RS/GS Eclipse and I have yet to find someone online who has done the swap and has done a write up. Something I may consider with my car if I ever find out how to actually do it.