The GTR Transmission is prone to gearbox syncromesh damage due to overselection from the factory hardware. Put in laymans terms the transmission is shifted until the selector bangs against the stoppers on the dog ring.
WR35GS Gear Stops are a set of specially machined 'stoppers' that control the gear selection distance at the driven end of the process - ie. they control the hydraulic piston travel and pull the selector up just short of the stoppers on the synchro ring. This means that gears can shift without mechanical damage in the transmission cause via over-selection. The WR35GS kit contains eight machined stoppers that only require the valve body of the transmission to be removed to fit, which makes it an attractive transmission upgrade without requiring full disassembly.