I don't think slammage is really for function, it really doesn't make the car do anything better (drag coefficient...no
). Better handling results from lowering the car on stiffer suspension, but not slamming it. Seems to me the main reason people slam is for looks, because it usually does look good. And I think this holds water because a lot of 6GA owners who don't go to big lengths to make their car faster acknowledge the fact these cars are slow, and just decide to at least make it look good.
That said, slamming is purely a motive for form. It can look good if done right, but that's about it. My opinion.