You know I've also noticed this. Obviously the price is better than the $170 Boomba charges for their BOV.
To Boomba's credit, I'm sure a lot more go into an actual BOV. While I'm not sure the BOV is worth the money to me I would also say this plate seems a bit expensive for a small piece of metal.
Reviews look good, but I'm always skeptical about reviews. He accepts returns so if anything buy it and return it if anything goes wrong. Also eBay has your back when making purchases of defective products.
You can't tune a BOV to work on this car. You don't run a BOV on this car. Doesn't work properly.
It's a plate that goes in between your stock oem recirc valve diaphragm and blocks the recirc air port forcing the boost to vent to atmosphere through the plate instead of recirculating back into the system between shifts and even partial throttle. You'll get that loud blow off sound for sure. It's a cheaper alternative to buying a VTA BOV. Since our cars are MAF and already takes the recirc air into consideration I wouldn't recommend it. It'll run peg rich when it vents. Not worth the clogged cats later on down the road in my opinion. It'll do more harm than good.
It's an endless debate on whether or not it hurts performance. Some will slap a bov on just for the sound anyways. Theres quite a few threads that cover it. In the end it is your vehicle and its up to you if you want to run one or not. Here's a link that covers a little bit on it.
