I bought my GFB BOV a year ago and went thru a lot of on/off periods with it. the product itself is fine: it makes the right noise, does not backfire under full atmosphere mode, works well in hybrid, its easy to install/uninstall. I bought mine at a good price of $150 shipped (new) from ninos auto. Even at this price, I feel it isnt worth it. A lot of people say they can notice the turbo lag difference, but in my opinion, they are just trying to justify spending $150+ on a product that just makes a whoosh noise. If you want to buy a $150 noisemaker that is your choice, for me, I'd rather put the $150 into something more worthwhile.
EDIT: I ended up selling this product. If any were interested.