I'm not sure where the "rice" comment was directed ...
... but my experience with a Kamei spoiler would suggest the first two would definitely help with aerodynamics, and I can't see how the bottom one would hurt.
The last one is a bumper cover so it may work with a Kamei or the other two if a bumper were added so the bumper cover could be used.
I didn't see the bumper cover listed at the site for sale at $299 or any other price although they do have pics incorporating it.
I'm not sure how any of the items are "rice." Then again, I am no expert on where things belong on labeled shelves ... I only know what I like and don't like.
(I see the middle one didn't post as a pic. Oh well.)