You have to use 2 butter knives or anything strong and flat on the top and bottom of the vent and carefully push them deep in around the plastic of the vent this will discloate the two clips holding this part in.
Now really carefully pull on the vent itself with some long nose pliers with a rag to stop it marking the vent, Now the whole asembly should come with some patience.
Once removed take out your stereo and storage bin or whatever you have below and I used a dremel to cut a hole for the wires of the guages to go behind the dashboard.
once you done this run your wires through one of the grommets to your bulkhead or remove front driver wheel and arch liner to reveal a bit grommet that the main loom run through. I just stabbed a screwdriver through here and pulled the wires through and then pocked them through the small hole that goes into engine bay.
Job Done!!!!