mud flaps

I recently bought some plastic Mustang mud flaps on Ebay for $37 that are supposed to be made by Ford and universal. if you follow the poor instructions that come with them they do not look right (if you drill three holes to mount them). Mount them with the two lower holes instead. You do not...

I have a 2007 Mustang and was wondering if i should add some rear mud flaps?? If i did i would want some low profile (no big ugly one). So what is your guys 2 cents on mud flaps. LIke them , Hate them and what kinda and brand? Thanks