Just got new Crossfire, has 80,000 miles on it, stock N/A limited, No modifications have been done. Would it be safe to use 1 heat range colder even if down the road I do not do any significant modifications? Or should I stay with the stock heat range plugs? Just making sure I get the right ones.

 

The only reason you need colder plugs is for forced induction or nitrous...
stock is fine for you