I have the FSwerks Stealth on my focus. It has a really nice sound, especially once you get some miles on it. I've gotten several compliments from other car guys on the tone. It's not raspy and whiny at all. There is a bit of drone, but it's not incredibly noticeable even at interstate speeds.
FSwerks Stealth exhaust. FSwerks ITG intake. FSwerks RMM. Eibach front & rear Sway bars.