GFB 03-10 Evo 8-10 Deceptor Pro II Blow Off Valve KitControl the sound of your BOV "ON THE FLY" Go on, admit it. There are times you wish you could have that signature turbo blow off sound, but you're not prepared to listen to it all the time. GFB's Deceptor Pro II delivers just what you need ? the ability to control how loud your BOV sound is, from the driver's seat. To top it off, if your car typically suffers issues such as backfiring and stalling when venting more than a certain percentage of air to