there is a panel air filter available here:
http://www.fensport.co.uk/parts/toyota/chr/chr-1-8-hybrid/engine-tuning/c-hr-1-8-hybrid-lm-panel-filter-blitz-59618/
but what noise and power you would get is unknown
http://www.fensport.co.uk/parts/toyota/chr/chr-1-8-hybrid/engine-tuning/c-hr-1-8-hybrid-lm-panel-filter-blitz-59618/
but what noise and power you would get is unknown