a standard spark plug should last 10-20K KM...those better/performance type should last 30-50KM....
Spark plug is wear and tear part...
Also life span of spark plug depend on your engine condition...if your engine makan engine oil / wrong tuning then your spark plug will wear out faster.
Nissan has finally launched the V36 Skyline Coupe 370GT to the Japanese market with 333ps under the hood, making it the most powerful V6 in its class...