well, a belt is a belt made of rubber. a chain is a chain made of metal. chains last alot longer than belts, but the down side is that its alot harder to replace the chain when it finally goes. for most RWD timing belts it only takes a couple of hrs to replace. a chain is alot longer and more involved to do. personally if its RWD i'd rather have a belt because its easier and cheaper to deal with. chains are stronger and last longer but are a pain in the ass to work on some times.