There is no camber adjustment stock, you must buy parts to get it.
-3 will accelerate wear on the inner shoulder if the car is driven daily.
Depending on the purpose a more modest angle will likely be adequate.
There's a couple very informative threads out there about the details.
http://www.ft86club.com/forums/showthread.php?t=25001
http://www.ft86club.com/forums/showthread.php?t=103609