He shouldnt have any problems doing that. Once he gets the HP tuner he can check for KR and if there is none, drop to one range colder plug and perhaps see if he can drop down to a 3.4 pulley. I definitely recommend the Autolite plugs, I think it would be 605's that are one range colder.
I believe its around 0.055 but 0.050 would be fine too.