How functional is the factory installed rear spoiler on a '97 850? Or is it just cosmetic?

I've been reading posts on various performance sites that generally cater to the "Honda-spaceship" crowd saying that rear spoilers provide downdraft, holding the car's rear-end on the road in curves or changing lanes at high speeds, may reduce the perceived effects of high winds at speed. Also, the posts tend to agree that poorly designed spoilers will increase drag, whereas the better engineered spoilers may reduce drag.

Nowhere have I found information about the Volvo spoilers. Any information here?

Thanks,

Chris
--
In the Country of the Blind, the One-Eyed Man is King