What's happening guys?....I'm a new Mini owner, picked my 2005 MCS back in November....i heard a rattle coming from the exhaust a couple days ago and noticed my resonator is rusted to *****....I just ordered a CAI and it should be here this week....i'm thinking about going one ball since the resonator is shot anyway....Between adding the CAI and the one ball mod 'm a little nervous, will this trigger a check engine light?.....

 

Being before (CAI) and after (exhaust resonator) any sensors, the car really has no idea you've done either of these. It'll be getting all the air it needs, and mods to the exhaust after the oxygen sensors should have no effect. Basically no chance these will cause a CEL.