I found the driver side and passeneger side very stiff to pull out when i done mine...id suggest carefully with a flat head screw driver behind the vent and carefully prise it out if u get the same prob...the dash is quite spongy so dont worry! Middle ones pull straight out with ease!
As for gear ring small thin flat head screwdriver the actual silver but pops out! Dont take the whole black plastic bit out with it!
Good luck its a nice mod with nice results