Mate, I bought an akrapovic silencer and it cost me $920 in Australia in oz dollars so you have either got a real cheap full system or they are ripping you for the silencer.
The guys i got mine off said that a whole system for the 525 is about the $1600 dollar mark for the silencer and head pipe...
In saying that once you bolt it on you wont regret it, make sure you run a jet kit through it, get a hole saw and cut a 2" hole in the left side of the airbox when the cover is removed (put the cover back on in the wet though) and you will be laughing.
I got my quad set up with a 15 tooth front, standard rear, 20" tyres. I weigh 110kg and it is bouncing on the rev limiter in 5th..
they are deffinatly worth the coin..