Any new spark plugs will help fuel economy and easier starting if your old ones needed to be replaced. It's called regular maintainence.
Originally posted by azmi222
If I understand it correctly the purpose of using different materials in plugs is to affect the temp of the spark itself. The Denso iridiums had a much higher spark temp.
No, the purpose of using different materials is to make them less affected by temperature. If you use a harder material like iridium it doesn't melt off in the same time frame and conditions like copper will. You won't be getting a hotter spark either if the conductor has a higher resistance. I would rather spend under $2 per plug and change out copper plugs on a regular basis than spending a lot more for plugs that I would still pull out and check on those regular intervals. There's been more than one occasion where all I've done is re-gapped my copper plugs and put them back in, back in business.