I have done a search on this but only found one IS430 and several NA IS300s with dual exhaust. I don't really want to get a 3" exhaust for turbo cos I found my existing 3" on my other car too loud! I was thinking dual exhaust with two mufflers might do a pretty good job without affecting flow too badly. Perhaps 2 X 2.5" pipes would do the trick. Any thoughts, comments or flames are welcome!