I currently have the HKS Hiper rear section on my IS and I like it but it is not deep/noticeable enough for me. I heard the Apexi N1 on another IS and is sounded REALLY MEAN/DEEP, it was exactly what I wanted. I do not know too much about Apexi products. Anyone here that actually has the N1 or any other Apexi exhaust, please advise. Any information is appreciated!