Selecting plugs

[BR3W CITY]

According to my Napa plug book, the stock plugs for my lq4 were an Iridium plug. When I go on Rock Auto they list everything from copper cheapies, to the IR plugs at almost $6 a pop. Whats the correct plug to use, and should I stick with a stock plug on a cam+injectors only motor?

[BAD LS1]

NGK TR55 V-Power.... Advance usually has them and its $15 for the set of 8. Gapped @.040"

[BR3W CITY]

Good looking out man.
I tried to meet you up at Dyno Days but ya always seemed busy! Let me know when you wanna get together, if you have any time later this week or weekend.