Technically the KE-Jet should run better, with the electronic control on the lambda, but it's a hybrid electo-mechanical system, which is a massive compromise, unlike the K-Jet, which is a nice, simple mechanical system. If I were you I'd bin the KE-Jet and fit an original KR K-Jet system. KE has a reputation for being difficult. You may need to check whether you need to swap out the fuel pump for a K-Jet one, too.