If you have a plenum spacer and HFCs and an aftermarket exhaust system with a cold air feed, then yes, it'll run leaner, but the ECU reigns it in a bit which is what brings up the EML. Will it do any damage? No, probably not, even though some members are like old ladies who panic about it and believe it does. Having said that, no zed is the same. No idea if the spacer will work on those de-cats, all i can tell you is, spacers didn't work for my HFCs.