Hey ya all,
Im gonna have to replace my aerial now, however i have no clue on how to install the new one. It was, and still is, a standard up and down one.
Please Help

3rd gen?

It's a case of undoing a couple of bolts, disconnecting the antenna lead, disconnecting the water drain tube, and throwing the old one out. Watch around the sub-frame, it's only punched aluminium and it's bloody sharp. Expect to get cut.

EDIT: you will also need to remove the nut that is on the outside of the car, on the very top where the antenna comes out. It looks basically circular, but there are two flat edges. This is the nut. Get a shifter and undo it completely - WATCH YOUR PAINTWORK! There are a few pieces that will try to run away (one rubber, one silver metal if I remember), make sure you get them, you will need to put them back on with the new antenna.

Get the new one, and do in reverse.

I went from a manual antenna to a power one. Cost $170 for the antenna and just had to plumb the remote wire in from the head unit down the back, and a power wire into the loom near the boot light.

Took me 40 mins to do. I could do a standard replacement in 20 mins.