Just did this as well with 2 washers. Sounds pretty good. A little loud sometimes (I also just took out my intake silencer too which contributes to this) and it did drone a little on the highway at 60mph or so, but for the most part, it sounds pretty damn mean. I'll keep it for a whlie, at least it is easy to change back. I did drop a washer down the y pipe but started the car up and it flew right out!