hi, i managed to take out the factory hu on my astra 1.6 sxi, but i cant seem to get the existing cage out? theres screws on either side and one on the back, but dunno wot kind of screws they are? a normal cross screwdriver doesnt work, neither does the hex , wot should i be using? also the pins at the back for power and speakers are they fixed to the cage? can they be freed ? im trying to put my kenwood mask in, i can connect the kenwood cables to the pin but i cant slide the hu in coz of the cage, so any help on how i can take it out and will this free the pins at the back etc?