Who has any information on what can be done to CUPs to improve performance without invalidating my warranty. You can buy a works package for the Cooper S now that takes it over 200bhp and as long as they fit it your ok, if Renault don’t start doing something like this soon I’m sure people will just start getting frustrated and purchase something else. I’m desperate to start tinkering but I can’t afford not to have a 3-year warranty. HELP.