What kind of car do you have? I have 98' with the Duratec, and dual flows. Here is a video of how mine sounded right after I put them on. They've mellowed out alot since then (two weeks ago) and most of the rasp is gone now.
That link isn't working at this moment, however, it should be working shortly. Drexel's servers are all screwed up, as one of their drive arrays went south yesterday morning, so I've been without email and ftp for like 24 hours...sucks. Hopefully it'll be back up by noon Saturday.