I agree I don't think it looks 'bad', i've seen far worse body kits for these years and I can see that they would get more sales since there is no bodywork to do and you can remove it. I'd like to see one done with the lower front/rear valence tucked in so that the chrome bumper is the farthest out part like our years to match also. Just looks a little odd with the valence still pushing out so far.
Funny thing is I can't find any mention of these parts on their website that is linked, even searched for '09 Mustang', poor website promotion.
Jon