OEM timing belts were never intended for use with tuned engines!
Replacing worn or stretched timing belt might just save your engine!
COMPARISON : TOMEI vs OEM
TOMEI TIMING BELT FEATURES
The Nissan and Subaru belts have matching marks similar to those on the OEM belts, allowing the user to check the position of the belt in relation to the cam pulley and crank pulley correctly when installing the belt.