I called Scott at Stromung today (I've known him for a few years) and asked him if he made an exhaust for S13s. He said no, but as we started talking, is interest in perhaps making one was piqued. We're going to talk some more next week, but I was wondering if maybe anyone else would be interested. He makes them for B14 Sentras, and they are very well made pieces, with a great sound. And they're made in the US by real craftsmen, so you'd be supporting an American small business (you can feel good about it and you won't have to pay for the JDM brand name).