There really is no down side to split R , its not as loud as a DV you will here om a Subaru or Evo , but its still quite loud , with a cold air intake fitted the sound is amplified, its generally louder than a CAI and a 007P , there are no faults codes ....if you find you dont want the dumping sound you simply fit the blanking plate suppplied and set it back to full recirc..........