zenki means in japanese: early, before, first, etc
kouki: late, last, later, etc
they're words in japanese, everyone just refers them to as zenki bumpers or kouki bumpers, instead of saying "early type" or "late model type", they are NOT brands, so people will laugh at you if you say "i want the bumper made by kouki"
these bumpers are original equipment off the AE86s in Japan, and other countries, they do not meet the safety regulations in North America, thats why we got different ones with a reinforcement bar
side skirts and bumpers can be obtained if you have sources in japan, or occasionally they're for sale in club4ag.com
also they are tons of afermarket bumpers and sideskirts for this car, but i'm sure you can do the research yourself in google.com