hi
when you fitted the new cable did you set the quadrant right before attaching it as if the problem has just started it would be best to disconnect clutch cable at gearbox end first then reset the clutch quadrant make sure the pawl is on the smooth bit of quad before you reattach it then connect gearbox end i know its a pain taking out the metering unit on mfi setup cars to get to cable properly but thats life as if you dont set it right it might not be disengaging fully and that will knacker your clutch or might be the box synchromesh
have you upgraded the power of the engine resently to exceed the clutches handling power
do you rag the car to much as the rs box aint to good with loads of torque as i have found out the costly way
mark2