Having owned an STI stock muffler, a cannon, and a twin exit oval muffler... I'd go the oval any day. Much more pleasant sitting on higher revs (3k was unbearable with the cannon, but is only noticeable with the oval muffler), yet if you give it shit or feather the throttle decelerating, it'll still burble and make all the usual noises.

If it's a daily vs a weekend car, it might play a bit differently though. I got really tired of losing the 'lets see if we can make it home without waking the surrounding 1km radius up' game when coming home at night, or not being able to have a conversation with someone in the car. If it was a weekender, I wouldn't say these things would worry me as much.

Have been followed & stopped by Police too, and they haven't even as much commented on the car let alone the exhaust. Didn't really with the cannon on either, though.