Spark plugs: Standard, Hot, Or Cold, Which type?

[chris_randolph]

I have 98 I30 with about 125,000 miles on it. I am going to go ahead and change the plugs, and I need to know which type is the best. I live down in the South, Mississippi, to be exact. The temperature down here ranges from about 60 F to 100 F. I do a ton of highway driving, cruising at about 90 mph. I use 91 octane fuel. Everyhing on the car is stock. I would like to get the best fuel economy. Thanks in advance.

[audtatious]

Just get the recommended (factory rated) set of NGK plugs. Should work just fine...