OK, nice motors..
COnvention on UK zed's is that any mods get cancelled out by the ECU learning and correcting.
People tend to do CAI, (AEM.JWT.etc) , Plenum Spacers (Smooths midrange) and Exhaust mostly for pleasant noises.
RS Tuning apprently are just about to be able to flash the ECU I think, there will be a long queue if they prove that they can
I think they are in Leeds.