the f2 type 2's have been damn near the worst suspension i've had on any car i've owned. one blew two days after i installed them, another five months later. i bought them brand new directly from function form. if i didn't need my car daily and would've had another suspension to put on it, i would've returned them after the first one blew...but from what i've heard of their customer service, i'm not sure how well that would've worked out either. for a comparison, the ksports i had before them last for 5 years and about 45k miles before one started leaking, the other three were still going strong.
if i won a free suspension from function form, i'd give them money to keep it. it's trash.
one thing i find funny about function form is that they claim their suspension to be good on the street or the track...like most other suspension companies. only, i've never seen or heard of a legit, track going race car that runs any function form components. based on my experience, they'd be good at putting your car into the wall through failure and terrible handling.
i'd go with the tein's if those are the only two you're considering. tein's are at least a quality and proven product.