Does anyone know if the HKS Direct Drive Racing Suction intake will work for the S4, I heard it has to do with the MAF, the differences between the S4 and S5? Is this true? I'm really interested in buying one, i found a pretty good deal on one.

 

On a s4 you need a AFM adapter: HiGGi, RX7.com, and a few other sites carry them.
S5 you can just put it on the end of the AFM