With your special rebate (everyone else pays $2/copper), you're looking at $42 to cover 100,000 miles, which is nothing to sneeze at. That's $84 for the rest of us that can't find a good deal. The pulstars are like $75 (?) for the same 100,000 miles and would require 6 less plug changes. Most of us take at least 20 minutes, so that's at least 2 hours of your life you could spend getting laid or kicking hobos or something like working overtime. Let's say you make $30/hr on overtime... that's ~$35 after taxes in your pocket, making the total price of iridiums only $40.
Say you get a 3% increase in mileage from these over stock. 100,000 miles ought to save you ~$375 in gas over 5 years, resulting in you actually getting paid $335 when coupled with that OT you put in, just to install these plugs. If that all goes to gas, it means he can drive ~2,700 miles farther than you with the same money. Did I math right?
Stock vehicles come with iridiums and he's got a stock vehicle. Perfect.
Personally, I'd check and re-gap an iridium plug at 50,000 miles - at 70k, mine were baaaarely out of gap, but my mileage was starting to hurt.