They do actually appear to the AF120s, the bottom 2 at least. The AFs have more fan blades than the SP120s. Also, the coloured rings do help with the airflow too, as will the front grille. You might even hear a suction sound as you put the grille on with the fans running.

) fans then I can't recommend the OcUK & Silverstone fans enough. At the moment they are £6.26 for 3 so about 20% the cost of buying more traditional rad fans. At this price what do you have to lose?