JWT Balance Shaft Removal Kit (BSR) removes the balance shafts from the 2.5L engine and adds high RPM performance. The QR25DE comes equipped with a balance shaft taht spins at twice engine speed to generate an opposing inertial mass. Installation takes about 2 hours and is done completely from the lower pan cover. This kit comes complete with instructions.

The following "Ask Sarah" article was found in the December 2002 issue of NissanPerformanceMag.com and was written by Sarah Foster

Q: How safe is removing the balance shafts from my Spec V and what gains should I expect?

Sarah: The 180 degree firing interval of a 4 cylinder engine causes the engine to vertically shake. Balance shafts act as counterweights by spinning at twice the engine speed to damp out the vibration for that smooth floating in the clouds ride but their rotation causes a large frictional power loss. Balance shafts can also seize past the factory revlim causing major engine damage. And you thought the rod bearings would be your first problem on those high rpm runs! Removing the balance shafts has been dyno proven to gains of 7-8 whp. The removal is hardly noticeable with engine vibration and fairly simple. Remove the pan, cut off the drive chain to the balance shafts with a cutoff wheel, unbolt the balance shaft assembly, thread the oil passages, block with pipe plugs, and shorten the main cap bolts by the thickness of the balance shaft assembly. For the mechanically challenged, just get JWT's kit which includes everything you need but the tools (and labor!). Yes, dealerships might raise an eyebrow (when don't they???) but mods can only void your warranty if they are the direct cause of the malfunction (Magnuson Moss Act). A slight increase in engine vibration should not cause you any problems.