here's a chart for comparison
and direct from NGK technical sheet that will explain it better than i ever could
Spark Plug Service
As a rule, replacement spark plugs should have the same or better
service interval as the original plugs. Long-life platinum and iridium spark plugs cost a little more than standard spark plugs and are an excellent upgrade for engines that were not originally equipped with these types of plugs. So replace same with same or better - unless an engine that was originally equipped with long-life spark plugs has a plug fouling
problem due to high oil consumption. In this case, it doesn't matter what type of spark plugs you install because they won't last as long as normal. If the oil burning
problem cannot be fixed, switching to a slightly hotter plug may
help reduce fouling.
For performance applications, switching to a slightly cooler spark plug can reduce the risk of pre-ignition and detonation at high rpm and loads.
Choosing Racing Spark Plugs
Selecting the proper spark plugs for a performance engine can mean the difference between front of the pack and not finishing the race. When using this
guide, understand that race plugs are usually of a much colder heat range rating than standard automotive spark plugs. Colder spark plugs must be used in engines with increased cylinder pressures, higher temperatures and greater horsepower. Other factors such as fuel delivery (turbo, supercharged), fuel types and piston-to-head clearance will also affect proper plug selection.
Step 1: Shell Design - The first step in choosing the proper race spark plug is determining the plug type that your cylinder head/piston will accept. Thread diameter and pitch, thread length and shell seat, as well as hex size are all factors that will define what shell type works best for your engine.
Step 2: Electrode Design - The second decision is electrode design and configuration. Is it a fine wire center or standard electrode? Projected or non-projected? Full coverage 'J-Gap' or perhaps a cut-back or angled ground wire? A good rule of thumb is to attain as much projection into the cylinder as possible. But be aware of piston clearance that could prohibit projected spark plugs from being used.
Step 3: Heat Range - The third factor in choosing a race plug is heat range. Correct heat range is critical in maintaining peak performance throughout the duration of your race or event. Switching to a colder or hotter plug will not increase horsepower, but could affect engine performance. Choosing a plug that is too hot can result in preignition or detonation. A plug that is too cold could cause an engine to stumble, misfire or foul.
The main factors to consider in selecting the proper heat range are: type of race, methanol, specific output, nitro-meth, compression ratio, nitrous oxide, horsepower, super or turbo charging and racing fuel.