for 99.9% of the PERFORMANCE benefits of MGK (on an N/A(mildly modified or stock) engine.), and less than half the price, choose Autolite APP764 Double Plats(or Motorcraft equiv.). If your goal is ABSOLUTE performance, sure, go with the NGK's...
For those of us who don't have money to throw away, I would choose Autolites for their performance when weighed against anything, price being included as a factor.
Ray