I have a Blitz blow off valve for sale. I used it for about a year with no problems at all. It fits 02-03 wrx, it might fit the later models but you might have to check. I went back to stock and its just sitting in my storage. It comes with orginal box and instructions. This is the dual drive blow off value, you can have the psssshhhh sound or put on the filter for a more quiet sound. This bolts up to the stock intercooler and comes with everything you need to bolt on.

Asking $180

Thanks