I’ve had a quick look underneath to size up the job of cavity wax injection on my 1998 308. The main areas appear to be the chassis rails, to which there is obvious and easy access and the cills - to which there is not.
I am thinking of removing the cill plates and drilling a couple of 1/2" holes in the upper surfaces of the cills for the injection lance. I assume the cills contain only one longitudinal cavity each side (between the inner and outer) and there is no foam fill or other obstruction.
Has anyone done this job and have any tips?