i recently put on the pop charger about 3 days ago. i notice a bit more power/response around 2,800 +. as far as sound the car is tad bit more beefy i would say with the slight whistle around 3k. i dont hear it to much until i shift gears which sounds nice. my next mod will be the mrev2 + 5/16 spacer

 

Placebo effect really with the pop-charger. You're buying the sound not any performance!

 

i actualy didnt notice the sound until my brother mentioned it.