Smart ForTwo 451 (2007 - 2014) Engine Mount Insert - PFR68-120 Fitting the new insert, PFR68-120 Engine Mount Insert reduces engine movement caused by the torque reaction of the engine during acceleration and deceleration. Gains can be seen in power transfer to the road along with less stress on the exhaust downpipe, hoses and wiring.A small increase in NVH usually at idle should be expected when fitting an engine/transmission mount insert because you are effectively removing the original voiding and stiffening the mount between the engine/transmission and chassis. The performance benefits felt by fitting an uprated mount or insert come from blocking this voiding up, thus restricting engine movement. - NOTE: Price is for CAR KIT, NOT per bush… Powerflex price their bushes individually, but we have combined the quantities to make it simple!