How many spark plugs in a 2007 Yamaha YZF R6S?

The 2007 Yamaha R6S is a 599cc forward inclined in-line 4 cylinder engine. It uses 4 spark plugs that are accessible by removing the driver seat, lifting the front of the fuel tank, removing the air box and filter, the heat shields and finally the coils that connect to the tops of the plugs. At a dealer the service cost to replace plugs can be upwards of $400 due to the labor time needed to access them.