Thumbs up on the Ram mount for the GPS -- I have one and believe it's a fantastic product. You set it where you want it and it stays right there . . . until you loosen it up and reposition it.
On the silencers for the exhaust . . . I've been riding for a very, very long time and I have yet to see a single ATV that has had one of these mounted on it . . . I'm not sure how well they work.