Recommend a spark plug??

[93octane]

I'm about to change the spark plugs on my 99GT what spark plug should I use. The car is bone stock??? Platinum or Copper and what brand??? It comes with platinum from the factory why should I change to copper?? Thanks

 

[BAFMustangGT]

Copper NGK

 

[Dark Knight GT]

Isn't this a repost ?

If not, I use Motorcraft copper awsf-c12's. They're two steps colder than stock and work fine for me. Should you decide to use coppers, its best to change them yearly or every 10-12k miles.

 

[8yourZ06]

NGK TR6 copper plug