tidy bit of bodywork that is!
it's actually fairly clean underneath that is (minus the wheel well) - perfect excuse to cut it out and make it flat boot though

be sure to take the rear arch liner carpets out and check for rust there before comitting yourself any more. Sills are a common thing on them, but looks like you've caught yours in good time

EML will no doubt either be a lambda problem or the IMRC module..... again common issues.