No an extension does not make a difference (ie to rise the torque wrench above the rockers) as long as it a good quality extension and does not twist form the torque. You can get torque multipliers in a gear head format in a 4:1 ratio, so if you want 100ftlbs you set the torque wrench to 25lbs, you can also use what looks like an open end wrench , they come in various lenghts from 6", 12" 24", one end has a male 3/8 or 1/2 drive and the other end female to fit the torque wrench.
