damaging or no--cabin air filter

[roxy84]

i know there has been plenty of discussion on the lack of a cabin air filter in the yaris. its obvious there are filters that fit. i have read that the reason the filters are not in there is due to some heating/cooling issues. ive searched, but have been unable to confirm if this is true. are we talking about less efficient operation of the air conditioning. if so, then id just as soon put the cabin air filter in and see how the AC operates.

my concern is whether is was an engine overheating type problem when the cabin filter was in. i know the yaris is cheap, but surely toyota didnt design and build the car with the housing for the cabin filter only to not include filters with the car.

my gut feeling is the filters arent in th yaris due to some problems, but i havent been able to pin down exactly what problems may be caused.

does anyone know the real story?