i have the injen intake with SAFC and i can tell a huge difference. now injen intake alone there isn't too much difference. you add the safc you get just as much as the SRT intake but you have the option of tunability to your engine and environment and also your other modifications. if you want a good deal on an SAFCII+Injen Intake setup let me know. i can sell you those for a good deal. pm me.--matt