You'll find that is the case with lots of things automotive. Same product. "New design". Does the same thing. Costs 3x as much. I used the XP Iridiums simply because it is what they had in the store. The others will work just fine too.
As far as I know two things cause a spark plug to wear out
- Mechanical fatigue due to heating/cooling cycle
- and hysteresis (erosion) which is the eventual breakdown of the outer surface of a conductor. Not due to spark, just from the conduction of electricity.
The iridium or platinum coating will withstand erosion slightly better.
But that's a longevity improvement if anything. It's got nothing to do with performance. And it doesn't keep it from fatiguing and losing proper gap, in fact a coating can flake off because of fatigue.
Depends on what your doing with the truck, really.
My every day truck gets normal maint standard plugs. It would never know the dif.
The prerunner and the race truck get bosch plat 4s...Those two know the differnce, and I do too if it has base line plugs.