using bosch platinum +4
 

i'm wondering if using these plugs will create more heat resulting in piston damage. Any comments appreciated.

A number of forum member run them, have not seen reports of melted pistons.

No, they will not create more heat resulting in piston damage. It's a spark plug, not a blow torch. :D The plug itself can not create enough heat to damage any metal.

They won't create any more heat than any other plug in the same heat range. Nor will they provide a better spark. They are a gimmick. The arc is going to jump the space with the least resistance.

The electrodes will hold more heat and can cause pre-detonation.

What works better is cheap plugs, changed often, compared to overpriced plugs changed at each transmission replacement (if needed).

Over the years I have had probably hundreds of people switch to Plus 4's and probably only 2 complained about them, one wouldn't change his factory wires at around 100,000 and wondered why the Plus 4's didn't help him
The last set I ran, I switched out at around 88,000 miles when doing head gaskets and only because I wanted to try the new Bosch Fuson which I was not pleased with.
Oh, and no, the plugs will not cause overheating of the cylinders or predetenation.

There's a huge difference between having no problems with something, and any actual benefit (as opposed to perceived benefit).

IMHO things that lead owners to do it once and forget about it (150,000 mile coolant, life time brake fluid, life time transmission fluid, etc.) usually come back to bite you in your lifetime. I do not dispute that there may be performance gains at certain loads and rpms. If you like them, change them at some kind of interval. The D1 is so easy to change plugs on, nothing like the pull the-intake-method on my old Montero (about $450 for plugs at the stealership).

And Disco Mike's performance might be more noticed at his altitude vs. the 17 feet above sea level where I am. But I may well try a set next time I change plugs.

Google spark plug comparison. There's a chart some where showing less than a 2% HP gain over regular copper plugs. Probably not anything anyone would notice.