My first Glanza had a HKS Hi-Silent and I hated how quiet it was. I got the middle box cut out and a straight through pipe put in place and it sounded so much better in every aspect. Here is a quick video I found that I had of it. I can't remember the exact setup at that time but i know it was cat and middle box removed. [media]http://www.youtube.com/watch?v=8GqEpzIVFgQ&feature=youtu.be