MAKE SURE YOU CHANGE THEM WHEN THE MOTOR IS COLD!!!
DON'T OVERTOURQE THE PLUGS OR ELSE IT WILL STRIP THE THREADS AND YOU WILL ROCKET A PLUG OUT OF THE MOTOR WHEN YOU LEAST EXPECT IT!!! IT'S AROUND 13-14LBFT TO TIGHTEN THEM PROPERLY.
I NEVER USE A TOURQE WRENCH, I GO BY FEEL AND JUST MAKE SURE THEY ARE SNUG, BUT NOT OVERTOURQED.
IF YOU WANT YOU CAN USE A LITTLE LITTLE BIT OF ANTI-SIEZE ON THE THREADS AS GOOD MEASURE.