I had 150 ET slips on my 10' R/T within the first 10,000 miles. Had Mike(MGH) swap out the original oem plugs at 70,000 miles which looked fine, just little lean on a couple of them. Put 90,000 miles on her in 28 months of ownership using it as my daily for hauling cement bags around. It was still getting 21 mpg the day I sold her.
Hemi is a tough motor..., Id say enjoy her with confidence