All things lead to the spark plug. You can spend all the money you want in fancy intakes, cylinder heads, or engine management, but if you're not paying attention to the most important step in the ...

After 152,000 miles, how much power does our E92 M3 still put down? We take it to the dyno for a real-world test and swap out the spark plugs to see if we can regain any lost performance. Watch the ...