Fuel, air, and spark are the three elements that make any internal combustion engine run, and the higher the standard or delivery of these, the more performance you will gain from your bike.
 
There is no need to present NGK; they simply make quality spark plugs used by most motorcycle manufacturers world!
 
On your Suzuki DR-Z400, you will need x1 spark plug to freshen up your engine ignition capabilities! This spark plug also fits KLX250/300 and Vstrom (check the fitment section)